Track system

ABSTRACT

A track system includes an attachment assembly, a frame assembly connected to the attachment assembly including at least one wheel-bearing frame member. The track system further has leading and trailing idler wheel assemblies at least indirectly connected to the at least one wheel-bearing frame member, at least one support wheel assembly at least indirectly connected to the at least one wheel-bearing frame member, an endless track extending around the leading idler wheel assembly, the trailing idler wheel assembly, and the at least one support wheel assembly. At least one monitoring sensor connected to the endless track and including an array of sensing devices communicates with a track system controller for determining, at least indirectly, at least one of a state of the track system and a ground surface condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 62/728,161, filed Sep. 7, 2018, entitled “TrackSystem”, U.S. Provisional Patent Application Ser. No. 62/728,669, filedSep. 7, 2018, entitled “Track System”, U.S. Provisional PatentApplication Ser. No. 62/728,662, filed Sep. 7, 2018, entitled “TrackSystem”, U.S. Provisional Patent Application Ser. No. 62/728,673, filedSep. 7, 2018, entitled “Track System”, U.S. Provisional PatentApplication Ser. No. 62/728,690, filed Sep. 7, 2018, entitled “Vehicle”,and U.S. Provisional Patent Application Ser. No. 62/728,697, filed Sep.7, 2018, entitled “Track System”. Each one of these patent applicationsis incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present technology relates to track systems for vehicles.

BACKGROUND

Certain vehicles, such as, for example, agricultural vehicles (e.g.,harvesters, combines, tractors, etc.) and construction vehicles (e.g.,bulldozers, front-end loaders, etc.), are used to perform work on groundsurfaces that are soft, slippery and/or uneven (e.g., soil, mud, sand,ice, snow, etc.).

Conventionally, such vehicles have had large wheels with tires on themto move the vehicle along the ground surface. Under certain conditions,such tires may have poor traction on some kind of ground surfaces and,as these vehicles are generally heavy, the tires may compact the groundsurface in an undesirable way due to the weight of the vehicle. As anexample, when the vehicle is an agricultural vehicle, the tires maycompact the soil in such a way as to undesirably inhibit the growth ofcrops.

In order to reduce the aforementioned drawbacks, to increase tractionand to distribute the weight of the vehicle over a larger area on theground surface, track systems were developed to replace at least some ofthe wheels and tires on the vehicles. For example, under certainconditions, track systems enable agricultural vehicles to be used in wetfield conditions as opposed to its wheeled counterpart.

The use of track systems in place of wheels and tires, however, doespresent some inconveniences. One of the drawbacks of conventional tracksystems is that, under certain conditions, the endless track can be incontact with the ground while having an uneven load distribution acrossthe ground contacting segment of the endless track, i.e. the portion ofthe endless track contacting the ground. As such, since the load is notevenly distributed across the ground contacting segment, areas of theground contacting segment create high and low pressure spots on theground surface. The high pressure spots cause undesirable soilcompaction at different depth levels. In addition, the unevendistribution of the load along the ground contacting segment can lead topremature wear of some components of the track system. One factor thatleads to the uneven distribution of the load across the groundcontacting segment of an endless track under certain conditions is thatthe structural components of the track system do not always allow theendless track to conform evenly to the ground surface like a tire filledwith gas (air or nitrogen) does.

While it is possible to measure or estimate with sufficient accuracy theload distribution on the various structural components of a track systemunder static conditions, measuring or estimating the load distributionon the various structural components of a track system under dynamicconditions has proven to be challenging. The load distribution on thevarious structural components of a track system varies as the tracksystem travels over obstacles such as bumps, recesses, ditches, andpotholes. Even when the track system travels on a paved road, the loaddistribution on the various structural components can change dependingon the profile of the road (i.e. the crowned profile of the road). Theload distribution on the various structural components can also changebecause of the camber and toe-in/toe-out angles of the track systemrelative to the chassis of the vehicle, and even as the vehicle steersleft and right. When the load distribution on the various structuralcomponents of the track system changes, the load distribution across theground contacting segment of the endless track changes as well. As such,while a given configuration of the various structural components of atrack system can be selected so as to have an optimal load distributionacross the ground engaging segment of the endless track in someparticular conditions, the same configuration could lead to a suboptimalload distribution across the ground engaging segment of the endlesstrack in other conditions.

As such, there remains that there is a need for continued improvement inthe design and configuration of track systems so that the loaddistribution across the ground engaging segment of the endless track bemeasured or estimated accurately so that the configuration of the tracksystem be optimized in accordance with a predetermined objective.

SUMMARY

It is therefore an object of the present technology to ameliorate thesituation with respect to at least one of the inconveniences present inthe prior art.

It is also an object of the present invention to provide an improvedtrack system at least in some instances as compared with some of theprior art.

According to an aspect of the present technology, there is provided atrack system for use with a vehicle having a chassis. The track systemincludes an attachment assembly connectable to the chassis of thevehicle. The attachment assembly includes a multi-pivot assembly havinga first pivot extending longitudinally and defining a roll pivot axis,and a second pivot extending laterally and defining a pitch pivot axis.The track system further has a frame assembly disposed laterallyoutwardly from the attachment assembly and connected to the attachmentassembly. The frame assembly includes at least one wheel-bearing framemember. The frame assembly includes structural components of the tracksystem capable of supporting a material portion of the weight of thevehicle.

The track system further has an actuator for pivoting the frame assemblyabout the roll pivot axis. The term “actuator” is used to encompass anymechanical device, such as hydraulic, electric, pneumatic powereddevices, that can provide motion. In addition, the actuator isunderstood to be controlled using either one of a particular programrunning on a computer, an automated sequence of actions, and/or a manualoverride.

The track system further has a leading idler wheel assembly at leastindirectly connected to the at least one wheel-bearing frame member, atrailing idler wheel assembly at least indirectly connected to the atleast one wheel-bearing frame member, and at least one support wheelassembly at least indirectly connected to the at least one wheel-bearingframe member. In the context of the present technology, thequalification of a wheel assembly as “at least indirectly connected”includes a wheel assembly that is directly connected to the at least onewheel-bearing frame member as well as a wheel assembly that is connectedto the wheel-bearing frame member through an intermediate structure orstructures, be they intermediate frame members or otherwise. The tracksystem also has an endless track that extends around the leading idlerwheel assembly, the trailing idler wheel assembly, and the at least onesupport wheel assembly.

The track system further has a monitoring sensor operatively connectedto the endless track and being configured to generate signals, and atrack system controller operatively connected to the monitoring sensor.The track system controller is configured to receive the signals fromthe monitoring sensor. It is to be noted that having a monitoring sensoroperatively connected to an endless track differs from having amonitoring sensor operatively connected to a tire in various ways.First, the dimensions of an endless track and a tire differconsiderably. For example, the thickness of the carcass of the endlesstrack differs from that of a tire, and the size and configuration of thetread on the outer surface also differ considerably. Second, the loadthey support differs considerably, not only because of the weight of thevehicle they support, by since a tire benefits from a cushion of airbetween the inner surface of the tire and the rim, some of the loadsupported by the tire is distributed throughout the materials of thecarcass because of the isostatic pressure applied by the cushion of air,while the endless track supports the load in a mostly uniaxialdirection. As such, the pressure peaks that an endless track has towithstand are generally much higher than in a tire supporting anequivalent load. Third, an endless track is subjected to greaterdeformations and fatigue problem during use as it has to wrap aroundidler wheel assemblies. As such, there are various challenges and issuesto using a monitoring sensor designed for use in a tire in a tracksystem. Finally, mud and debris ingress a track system and the innersurface of the endless track is exposed to such contaminants, whereasthe inner surface of a tire is not exposed.

In some embodiments of the track system of the present technology, themonitoring sensor is configured to generate first signals indicative ofa load parameter supported by the endless track.

The track system of the present technology is directed towards reducingsoil compaction issues under certain conditions. For example,improvements in reducing soil compaction issues might be perceived whenthe track system pivots about the roll pivot axis as it travels over aground surface that is sensitive to soil compaction, such as anagricultural field. When the frame assembly pivots about the roll pivotaxis, the leading idler wheel assembly, the trailing idler wheelassembly, and the at least one support wheel assembly also pivot and canbetter conform to the profile of the ground surface such that the loadapplied by the wheel assemblies is more evenly distributed across thesegment of the endless track engaging the ground on soil which issensitive to compaction. The actuator controls the pivot motion of theframe assembly relative to the attachment assembly and enables theselection of the camber angle of the track system relative to thechassis of the vehicle.

In some embodiments, the monitoring sensor includes a strain gauge.

In some embodiments. The monitoring sensor includes an array of straingauges.

In some embodiments of the track system of the present technology, themonitoring sensor includes a load cell. Load cells are understood toencompass transducers that create an electrical signal whose magnitudeis proportional to a force being measured.

In some embodiments of the track system of the present technology, themonitoring sensor includes an array of load cells.

In some embodiments of the track system of the present technology, themonitoring sensor is configured to generate second signals indicative ofa vibration parameter undergone by the endless track.

In some embodiments of the track system of the present technology, themonitoring sensor includes an accelerometer.

In some embodiments of the track system of the present technology, themonitoring sensor includes an inclinometer.

In some embodiments of the track system of the present technology, themonitoring sensor is configured to generate third signals indicative ofa temperature parameter of the endless track.

In some embodiments of the track system of the present technology, themonitoring sensor includes at least one of a thermocouple and athermistor.

In some embodiments of the track system of the present technology, themonitoring sensor is embedded in the endless track.

In some embodiments of the track system of the present technology, themonitoring sensor is a flexible mat structured and dimensioned to extendover a majority of a width of the endless track.

In some embodiments of the track system of the present technology, themat is structured and dimensioned to extend along a majority of a lengthof the endless track.

In some embodiments of the track system of the present technology, themonitoring sensor includes a flexible foil connected to an inner surfaceof the endless track.

In some embodiments of the track system of the present technology, thefoil is structured and dimensioned to extend over a minority of a widthof the endless track.

In some embodiments of the track system of the present technology, thefoil is structured and dimensioned to extend along a majority of alength of the endless track.

In some embodiments of the track system of the present technology, themonitoring sensor includes a flexible foil connected to an outer surfaceof the endless track.

In some embodiments of the track system of the present technology, thefoil is structured and dimensioned to extend over a minority of a widthof the endless track. In some embodiments of the track system of thepresent technology, the foil is structured and dimensioned to extendalong a majority of a length of the endless track.

In some embodiments of the track system of the present technology, themonitoring sensor includes a layer of networked sensors. In someembodiments of the track system of the present technology, themonitoring sensor includes an elementary structure of networked sensors.As such, the monitoring sensor may be structured differently than themat and flexible foil described above.

In some embodiments of the track system of the present technology, themonitoring sensor includes first and second flexible foils. The firstfoil is connected to an inward portion of the inner surface of theendless track and the second foil is connected to an outward portion ofthe inner surface of the endless track.

In some embodiments of the track system of the present technology, themonitoring sensor is connected to the endless track after amanufacturing of the endless track.

In accordance with another aspect of the present technology, there isprovided a track system for use with a vehicle having a chassis, thetrack system including an attachment assembly connectable to the chassisof the vehicle, a frame assembly disposed laterally outwardly from theattachment assembly and connected to the attachment assembly, the frameassembly including at least one wheel-bearing frame member, a leadingidler wheel assembly at least indirectly connected to the at least onewheel-bearing frame member, a trailing idler wheel assembly at leastindirectly connected to the at least one wheel-bearing frame member, atleast one support wheel assembly at least indirectly connected to the atleast one wheel-bearing frame member and disposed between the leadingidler wheel assembly and the trailing idler wheel assembly, an endlesstrack extending around the leading idler wheel assembly, the trailingidler wheel assembly, and the at least one support wheel assembly, atleast one monitoring sensor connected to the endless track, the at leastone monitoring sensor including an array of sensing devices and beingconfigured to generate at least one signal, the at least one monitoringsensor determining, at least indirectly, at least one of a state of thetrack system and a ground surface condition, and a track systemcontroller communicating with the at least one monitoring sensor forreceiving the at least one signal indicative of the at least one of thestate of the track system and the ground surface condition.

In some embodiments, the at least one monitoring sensor is configured togenerate a first signal indicative of a load parameter supported by theendless track.

In some embodiments, the at least one monitoring sensor includes atleast one of strain gauges and load cells.

In some embodiments, the at least one monitoring sensor is configured togenerate a second signal indicative of a vibration parameter undergoneby the endless track.

In some embodiments, the at least one monitoring sensor includes atleast one of an accelerometer and an inclinometer.

In some embodiments, the at least one monitoring sensor is configured togenerate a third signal indicative of a temperature parameter of theendless track.

In some embodiments, the at least one monitoring sensor includes atleast one of a thermocouple and a thermistor.

In some embodiments, the at least one monitoring sensor is embedded inthe endless track.

In some embodiments, the at least one monitoring sensor is a flexiblemat structured and dimensioned to extend over a majority of a width ofthe endless track.

In some embodiments, the at least one monitoring sensor is structuredand dimensioned to extend along a majority of a length of the endlesstrack.

In some embodiments, the at least one monitoring sensor includes aflexible foil connected to an inner surface of the endless track.

In some embodiments, the foil is structured and dimensioned to extendover a minority of a width of the endless track.

In some embodiments, the foil is structured and dimensioned to extendalong a majority of a length of the endless track.

In some embodiments, the at least one monitoring sensor includes firstand second flexible foils, the first foil is connected to an inwardportion of the inner surface of the endless track, and the second foilis connected to an outward portion of the inner surface of the endlesstrack.

In some embodiments, the at least one monitoring sensor is connected tothe endless track after a manufacturing of the endless track.

In some embodiments, the attachment assembly includes a multi-pivotassembly having a first pivot extending longitudinally and defining aroll pivot axis of the track system, the frame assembly being pivotableabout the roll pivot axis, and a second pivot extending vertically anddefining a yaw pivot axis of the track system, the frame assembly beingpivotable about the yaw pivot axis. The track system further includes atleast one actuator connected between the attachment assembly and theframe assembly for pivoting the frame assembly about at least one of theroll pivot axis and the yaw pivot axis, and the track system controlleris configured to connect to and to control the operation of the at leastone actuator based on the at least one of the state of the track systemand the ground surface condition.

There is also provided a vehicle including first and second tracksystems as described above, with the track system controller of thefirst track system is at least indirectly connected to the track systemcontroller of the second track system for receiving the at least onesignal indicative of the at least one of the state of the track systemand the ground surface condition determined by the at least onemonitoring sensor of the second track system.

In accordance with yet another aspect of the present technology, thereis provided an endless track for a track system. The endless track hasat least one monitoring sensor including an array of sensing devices fordetermining, at least indirectly, at least one of a state of the tracksystem and a ground surface condition. The at least one monitoringsensor is structured and dimensioned to extend along a majority of alength of the endless track.

In some embodiments, the at least one monitoring sensor is structuredand dimensioned to extend over a minority of a width of the endlesstrack.

In some embodiments, the at least one monitoring sensor is structuredand dimensioned to extend along a majority of a width of the endlesstrack.

Should there be any difference in the definitions of term in thisapplication and the definition of these terms in any document includedherein by reference, the terms as defined in the present applicationtake precedence.

Embodiments of the present technology each have at least one of theabove-mentioned object and/or aspects, but do not necessarily have allof them. It should be understood that some aspects of the presenttechnology that have resulted from attempting to attain theabove-mentioned object may not satisfy this object and/or may satisfyother objects not specifically recited herein.

Additional and/or alternative features, aspects, and advantages ofembodiments of the present technology will become apparent from thefollowing description, the accompanying drawings, and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present technology, as well as otheraspects and further features thereof, reference is made to the followingdescription which is to be used in conjunction with the accompanyingdrawings, where:

FIG. 1 is a right side elevation view of a track system being anembodiment of the present technology configured to be operativelyconnected on a right side of a vehicle;

FIG. 2 is a partially exploded, rear elevation view of a vehicle havingthe track system of FIG. 1 operatively connected to the right sidethereof, and another track system being a mirror image of the tracksystem of FIG. 1 operatively connected to the left side thereof;

FIG. 3A is a rear elevation view of the track system of FIG. 1, with theendless track removed, and the frame assembly and wheel assembliespivoted at a negative camber angle;

FIG. 3B is a rear elevation view of the track system of FIG. 3A, withthe frame assembly and wheel assemblies pivoted at a positive camberangle;

FIG. 4A is a front elevation view of the vehicle of FIG. 2 with the leftand right track systems having a neutral camber angle;

FIG. 4B is a front elevation view of the vehicle of FIG. 4A, with thevehicle bearing an increased load and the left and right track systemshaving a positive camber angle;

FIG. 5 is a top plan view of the track system of FIG. 1, with theendless track removed, and the frame assembly and wheel assembliespivoted at a toe-in angle;

FIG. 6 is a top plan view of the track system of FIG. 5, with the frameassembly and wheel assemblies pivoted at a toe-out angle;

FIG. 7 is a right side elevation view of the track system of FIG. 1,with the leading idler wheel assembly raised;

FIG. 8 is a right side elevation view of the track system of FIG. 1,with the trailing idler wheel assembly raised;

FIG. 9 is a right side elevation view of the track system of FIG. 1travelling on an uneven terrain, with the trailing idler actuatorretracted and the leading idler actuator extended;

FIG. 10A is a right side elevation view of the track system of FIG. 1,with the leading and trailing idler wheel assemblies raised;

FIG. 10B is a partially exploded, perspective view taken from a front,top right side of the track system of FIG. 1, with the endless track andone idler wheel of the leading and trailing idler wheel assembliesremoved;

FIG. 11 is a right side elevation view of the track system of FIG. 1,with the damper in the fully extended position;

FIG. 12 is a right side elevation view of the track system of FIG. 11,with the leading and trailing idler wheel assemblies raised;

FIG. 13 is a right side elevation view of the track system of FIG. 1,with the damper in the fully compressed position;

FIG. 14 is a right side elevation view of the track system of FIG. 13,with the leading and trailing idler wheel assemblies raised;

FIG. 15 is a right side elevation view of the track system of FIG. 1 ina rest configuration and stationary;

FIG. 16 is a right side elevation view of the track system of FIG. 1,with the leading and trailing idler wheel assemblies raised andstationary;

FIG. 17A is a top plan, schematic view of the vehicle of FIG. 2 withtrack systems operatively connected thereto at each of the four corners;and

FIG. 17B is a top plan, schematic view of the vehicle of FIG. 17Afurther including a master control unit and a communication device;

FIG. 17C is a top plan, schematic view of the vehicle of FIG. 17A,further including a communication device and a remote master controlunit;

FIG. 18 is a left side elevation view of the vehicle of FIG. 2 with thetrack system being a mirror image of the track system of FIG. 1operatively connected to the left side thereof;

FIG. 19 is a perspective view taken from a top, right, rear side of theendless track of the track system of FIG. 1, with a mat embedded withinthe endless track shown in phantom lines;

FIG. 20 is a right side elevation view of the endless track of FIG. 19;

FIG. 21 is a cross-sectional view of the endless track of FIG. 19 takenalong cross-section line 21-21 of FIG. 20;

FIG. 22 is a fragmented, top plan view of the inner surface of theendless track of FIG. 19;

FIG. 23 is a perspective view taken from a top, right, rear side of theendless track of the track system of FIG. 1, with foils connected toinward and outward portions of the inner surface of the endless track;

FIG. 24 is a cross-sectional view of the endless track of FIG. 23 takenalong cross-section line 24-24 of FIG. 23; and

FIG. 25 is a top plan view of the inner surface of the endless track ofFIG. 23.

DETAILED DESCRIPTION Introduction

With reference to FIGS. 1 to 14, an embodiment of the presenttechnology, track system 40, is illustrated. It is to be expresslyunderstood that the track system 40 is merely an embodiment of thepresent technology. Thus, the description thereof that follows isintended to be only a description of illustrative examples of thepresent technology. This description is not intended to define the scopeor set forth the bounds of the present technology. In some cases, whatare believed to be helpful examples of modifications or alternatives totrack system 40 may also be set forth below. This is done merely as anaid to understanding, and, again, not to define the scope or set forththe bounds of the present technology. These modifications are not anexhaustive list, and, as a person skilled in the art would understand,other modifications are likely possible. Further, where a modificationhas not been done (i.e. where no examples of modifications have been setforth), it should not be interpreted that no modifications are possibleand/or that what is described is the sole manner of implementing orembodying that element of the present technology. As a person skilled inthe art would understand, this is likely not the case. In addition, itis to be understood that the track system 40 may provide in certainaspects a simple embodiment of the present technology, and that wheresuch is the case it has been presented in this manner as an aid tounderstanding. As a person skilled in the art would understand, variousembodiments of the present technology may be of a greater complexitythan what is described herein.

Referring to FIG. 2, the track system 40 is for use with a vehicle 60having a chassis 62 and a drive shaft 64 extending laterally outwardlyfrom the chassis 62 for driving the track system 40 (the vehicle 60, thechassis 62 and the drive shaft 64 are schematically shown in FIG. 2).The chassis 62 supports various components of the vehicle 60, such asthe cabin, the engine, the gearbox and other drivetrain components (notshown). In this embodiment, the drive shaft 64 is the drivetraincomponent that transmits the driving force from the engine and gearboxof the vehicle 60 to the track system 40, i.e. the drive shaft 64 is theoutput shaft of the gearbox.

In the context of the following description, “outwardly” or “outward”means away from a longitudinal center plane 66 of the chassis 62 of thevehicle 60, and “inwardly” or “inward” means toward the longitudinalcenter plane 66. In addition, in the context of the followingdescription, “longitudinally” means in a direction parallel to thelongitudinal center plane 66 of the chassis 62 of the vehicle 60 in aplane parallel to flat level ground, “laterally” means in a directionperpendicular to the longitudinal center plane 66 in a plane parallel toflat level ground, and “generally vertically” means in a directioncontained in the longitudinal center plane 66 along a height directionof the track system 40 generally perpendicular to flat level ground.Note that in the Figures, a “+” symbol is used to indicate an axis ofrotation. In the context of the present technology, the term “axis” maybe used to indicate an axis of rotation, or the term may refer to a“pivot joint” that includes all the necessary structure (bearingstructures, pins, axles and other components) to permit a structure topivot about such axis, as the case may be. Moreover, the direction offorward travel of the track system 40 is indicated by an arrow 80 inFIG. 1. In the present description, the “leading” components areidentified with a letter “l” added to their reference numeral (i.e.components towards the front of the vehicle 60 defined consistently withthe vehicle's forward direction of travel 80), and the “trailing”components are identified with a letter “t” added to their referencenumeral (i.e. components towards the rear of the vehicle 60 definedconsistently with the vehicle's forward direction of travel 80). In thefollowing description and accompanying Figures, the track system 40 isconfigured to be attached to a right side of the chassis 62 of thevehicle 60. A track system 40′ (FIG. 2), being another embodiment of thepresent technology and configured to be connected to a left side of thechassis 62 of the vehicle 60, is a mirror image of the track system 40with the necessary adaptations, and the components of the track system40′ are identified with a “′” added to their reference numeral. Thatembodiment will not be further described herein.

General Description of the Track System

Referring to FIGS. 1 to 6, the track system 40 will be generallydescribed. The track system 40 includes an attachment assembly 100connectable to the chassis 62 of the vehicle 60. The attachment assembly100 includes a multi-pivot assembly 110 having a longitudinallyextending pivot 112. The pivot 112 defines a roll pivot axis 114 of thetrack system 40. The multi-pivot assembly 110 further has a pivot 116extending laterally outwardly. The pivot 116 defines a pitch pivot axis118 of the track system 40.

The track system 40 further includes a frame assembly 200 disposedlaterally outwardly from the attachment assembly 100 (FIG. 2) andconnected thereto. The frame assembly 200 is a multi-member frameassembly and includes a leading frame member 210 l pivotably connectedto the attachment assembly 100 via the pivot 116 for pivoting about thepitch pivot axis 118 (FIG. 1), and a trailing frame member 210 tpivotably connected to the attachment assembly 100 via the pivot 116 forpivoting about the pitch pivot axis 118 (FIG. 1) independently from theleading frame member 210 l. The multi-member frame assembly 200 alsoincludes a leading wheel-bearing frame member 230 l pivotably connectedto a lower portion 222 l of the leading frame member 210 l. The leadingwheel-bearing frame member 230 l pivots about a pivot axis 224 l. Themulti-member frame assembly 200 further includes a trailingwheel-bearing frame member 230 t pivotably connected to a lower portion222 t of the trailing frame member 210 t. The trailing wheel-bearingframe member 230 t pivots about a pivot axis 224 t. A trailing supportwheel assembly 250 is pivotably connected to the trailing wheel-bearingframe member 230 t about an axis 252. The track system 40 furtherincludes a damper 300 (in this embodiment a shock absorber)interconnecting the leading frame member 210 l and the trailing framemember 210 t.

A leading idler wheel assembly 400 l is rotatably connected to theleading wheel-bearing frame member 230 l, and a trailing idler wheelassembly 400 t is rotatably connected to the trailing wheel-bearingframe member 230 t. A plurality of support wheel assemblies 410 a, 410b, 410 c are disposed between the leading idler wheel assembly 400 l andthe trailing idler wheel assembly 400 t. The support wheel assemblies410 a, 410 b, 410 c assist in distributing the load born by the tracksystem 40 across the endless track 600 of the track system 40. Thesupport wheel assembly 410 a is rotatably connected to the leadingwheel-bearing frame member 230 l. The support wheel assemblies 410 b,410 c are rotatably connected to the trailing support wheel assembly250.

Referring to FIGS. 1 to 6, the track system 40 further includes agearbox 500 (schematically shown in FIG. 2) operatively connected to thedrive shaft 64 of the vehicle 60. The drive shaft 64 is operativelyconnected to the gearbox 500 via a universal joint 510, but could beoperatively connected otherwise. The track system 40 further includes asprocket wheel 550 operatively connected to the gearbox 500. It is notedthat in the present embodiment, the drive shaft 64 of the vehicle 60does not bear a material portion of the weight of the vehicle 60 butonly transmits driving forces to the gearbox 500 which does not bear amaterial portion of the weight of the vehicle 60 either. In otherembodiments, the gearbox 500 could be omitted and the drive shaft 64could be directly connected to the sprocket wheel 550. In suchembodiments, the drive shaft 64 could be an axle of the vehicle 60 onwhich a tire and wheel assembly could be connected should a wheeledconfiguration be preferred to a configuration with track systems. Otherembodiments of the track system 40 could be designed to be used on avehicle and not be meant to be driven by a drive shaft 64. For example,other embodiments of the track system 40 could be configured to beoperatively connected to a towed vehicle, and thus such embodiments ofthe track system 40 would have no sprocket wheel 550. In suchembodiments the track system could have a generally rectangular shapeinstead of the generally triangular shape of the track system 40illustrated in the accompanying Figures.

Endless Track

The track system 40 further includes the endless track 600 (FIG. 1)which extends around the sprocket wheel 550, the leading idler wheelassembly 400 l, the trailing idler wheel assembly 400 t, and theplurality of support wheel assemblies 410 a, 410 b, 410 c. The endlesstrack 600 is drivable by the sprocket wheel 550.

The endless track 600 is an endless polymeric track. The endless track600 has an inner surface 602 engaging the leading idler wheel assembly400 l, the trailing idler wheel assembly 400 t, and the plurality ofsupport wheel assemblies 410 a, 410 b, 410 c. Lugs 604 (FIG. 18) aredisposed on a central portion of the inner surface 602 and areengageable by the sprocket wheel 550. As such, the track system 40 is a“positive drive” track system. Friction drive track systems are alsocontemplated as being an alternative to the present embodiment. Theidler and support wheel assemblies 400 l, 400 t, 410 a, 410 b, 410 chave laterally spaced-apart wheels (FIGS. 5 and 6) engaging the innersurface 602 of the endless track 600 on either side of the lugs 604 toprevent the endless track 600 to slide off. The endless track 600 alsohas an outer surface 606 with a tread 608 (FIGS. 4A and 4B) selected forground engagement. The tread 608 varies in different embodimentsaccording to the type of vehicle on which the track system 40 is to beused with and/or the type of ground surface on which the vehicle isdestined to travel. It is contemplated that within the scope of thepresent technology, the endless track 600 may be constructed of a widevariety of materials and structures including metallic components knownin track systems.

Referring to FIGS. 7 and 8, the endless track 600 has a leading segment610, a ground engaging segment 620 and a trailing segment 630. Asmentioned above, the generally triangular shape of the track system 40causes the endless track 600 to have the segments 610, 620, 630, but asother configurations of the track system 40 are contemplated, theendless track 600 could have more or less segments in other embodiments.Referring to FIGS. 7 and 8 and as will be described below, the pivotalpositioning of the leading idler wheel assembly 400 l relative to theleading frame member 210 l and the pivotal positioning of the trailingidler wheel assembly 400 t relative to the trailing frame member 210 tvaries by raising or lowering the leading wheel-bearing frame member 230l and the trailing wheel-bearing frame member 230 t respectively. Whenthe leading wheel-bearing frame member 230 l is raised (FIG. 7), theground engaging segment 620 includes a leading ground-engaging segment622 l that extends above ground when the endless track 600 is disposedon flat level ground. The leading ground-engaging segment 622 l extendsbelow the leading idler wheel assembly 400 l. It is contemplated that,in certain situations such as when the track system 40 travels on softground and compacts the medium forming the ground, the ground-engagingsegment 622 l could engage the ground surface.

When the trailing wheel-bearing frame member 230 t is raised (FIG. 8),the ground engaging segment 620 further includes a trailing groundengaging segment 622 t that extends above ground when the endless track600 is disposed on flat level ground. The trailing ground engagingsegment 622 t extends below the trailing idler wheel assembly 400 t. Itis also contemplated that, in certain situations such as when the tracksystem 40 travels on soft ground and compacts the medium forming theground, the ground-engaging segment 622 t could engage the groundsurface. Referring to FIG. 10A, when both the leading wheel-bearingframe member 230 l and the trailing wheel-bearing frame member 230 t areraised, the endless track 600 has the leading ground-engaging segment622 l and the trailing ground engaging segment 622 t extending aboveground. In this configuration, the ground engaging segment 620 (i.e. theportion of the endless track 600 that engages the ground surface whenthe endless track 600 is disposed on flat level ground) is shortercompared to the ground engaging segment 620 of the configurations shownin FIGS. 1, 7 and 8.

Attachment Assembly

Turning back to FIGS. 2 to 6, the attachment assembly 100 will bedescribed. The multi-pivot assembly 110 has a yoke 120. The yoke 120 isconnected to the chassis 62 of the vehicle 60. In the presentembodiment, the yoke 120 is connected to an underside of the chassis 62,but could be configured and structured to be connected to the chassis 62otherwise. The yoke 120 has longitudinally spaced apart tabs 122 (FIGS.5 and 6). The tabs 122 each define a hole (not shown) through which thelongitudinally extending pivot 112 extends. A pivot arm 124 is pivotablyconnected to the tabs 122 of the yoke 120 by the longitudinallyextending pivot 112. The pivot arm 124 is a cruciform membersimultaneously connected to the pivot 112 and to a generally verticallyextending pivot 126. The pivot 126 defines a yaw pivot axis 128 of thetrack system 40. The pivot arm 124 is further pivotably connected to aplate 130 having vertically spaced apart tabs 132 (only the top tab 132is show). The tabs 132 each define a hole (not shown) through which thegenerally vertically extending pivot 126 extends. Through the pivot 126,the plate 130 is pivotable about the yaw pivot axis 128 relative to thepivot arm 124, and the plate 130 is thus pivotable relative to the yoke120 about the roll and yaw pivot axes 114, 128. It is to be noted that,in the present embodiment, the yaw pivot axis 128 extends in a directionparallel to the longitudinal center plane 66 and along a heightdirection of the track system 40 that is perpendicular to flat levelground. In another embodiment, the yaw pivot axis 128 could extend notperpendicularly to flat level ground and could be skewed forward orrearward so as to define a positive or negative caster angle of thetrack system 40.

As best seen in FIGS. 2 to 3B, the plate 130 has the pivot 116projecting therefrom and extending laterally outwardly from theattachment assembly 100. The pivot 116 is connected to the outward faceof the plate 130. The pivot 116 can be connected to the plate 130 usingfasteners and/or any bonding techniques such as welding. In someembodiments, the pivot 116 is integrally formed with the plate 130.Loads on the chassis 62 of the vehicle 60 (including the vehicle'sweight) are transferred to the plate 130 via the yoke 120 when connectedto the chassis 62. Loads are then transferred to the pivot 116 and thento the leading and trailing frame members 210 l, 210 t, and so on.

As will be described in more details below, the roll, pitch and yawpivot axes 114, 118, 128 permit degrees of freedom of the track system40 relative to the chassis 62 of the vehicle 60 that can assist theendless track 600 to better conform to the ground surface on which ittravels and in turn distribute more evenly the load on the entiresurface of the ground engaging segment 620 of the endless track 600.

Referring to FIGS. 3A to 4B, the attachment assembly 100 further has acamber angle adjusting actuator 140 operatively connected betweendownwardly projecting tabs 142 of the yoke 120 and downwardly projectingtabs 144 of the plate 130. The camber angle adjusting actuator 140 isthus downwardly offset of the pivot axes 114, 118. The actuator 140 is atelescopic linear actuator. Referring to FIGS. 3A and 3B, retraction andextension of the actuator 140 causes pivoting of the frame assembly 200and wheels 400 l, 400 t, 410 a, 410 b, 410 c about the roll pivot axis114 so as to adopt a negative camber angle −θ (FIG. 3A) or a positivecamber angle θ (FIG. 3B). In some embodiments, the camber angleadjusting actuator 140 can provide for camber angle adjustment of up toabout 10 degrees, that is angle θ equals to about 10 degrees, but largeror smaller angles θ are contemplated in different embodiments.

As best seen in FIG. 3A, extension of the actuator 140 causes the tracksystem 40 to adopt a negative camber angle −θ. Conversely and as seen inFIG. 3B, retraction of the actuator 140 causes the track system 40 toadopt a positive camber angle θ. As such, the track system 40 has arange of roll motion about the pivot axis 114 from about −10 degrees to10 degrees for adjusting the camber angle of the track system 40. Thedegree of freedom in roll motion about the pivot axis 114 permits thetrack systems 40, 40′ to better conform to a ground surface which isinclined laterally and that defines, for example, a crowned road or ashallow ditch.

As such, the load supported by the frame assembly 200 is more evenlydistributed between the inward and outward wheels of the idler andsupport wheel assemblies 400 l, 400 t, 410 a, 410 b, 410 c. This moreeven distribution of the load can reduce wear of the endless track 600as a majority of the area of the ground engaging segment 620 is inground contact, and not just and area below the inward or outwardwheels. Wear of the bearings and axle assemblies of each one of theidler and support wheel assemblies 400 l, 400 t, 410 a, 410 b, 410 c isalso reduced compared to track systems that do not have a degree offreedom in roll motion.

Referring to FIGS. 4A and 4B, the actuator 140 can also be used forselective adjustment of the camber angle θ as a function of the loadapplied on the track system 40. For example, as a load L of the vehicle60 increases, for example during harvesting or loading operations, thecenter portion of the chassis 62 deflects downwards under this increasedload L, which would tilt the track systems 40, 40′ at a negative camberangle −θ and causing the inward wheels of the wheel assemblies 400 l,400 t, 410 a, 410 b, 410 c to bear more load than the outward wheelassemblies. The actuator 140 can be selectively retracted so that thecamber angle θ be adjusted to compensate for this deflection (i.e. θ isequal to about 0 degree, which corresponds to a neutral camber angle).As such, in certain circumstances, the load could be more evenlydistributed across the ground engaging segment 620 of the endless track600. It is to be noted that in FIG. 4B, the camber angle θ is not toscale and is represented for illustrative purposes. Thus, operation ofthe actuator 140 could allow the track system 40 to have a dynamicallychanging camber angle θ depending on, for example, ground surfaceconditions, temperature in certain portions of the endless track 600and/or the load L born by the vehicle 60.

In other embodiments, the actuator 140 is replaced by a stepper motor orby any other devices capable of adjusting the positional relationshipabout the roll pivot axis 114 between the attachment assembly 100 andthe frame assembly 200. Thus, the actuator 140 could be replaced by astepper motor which could adjust the positional relationship by rotatingthe frame assembly 200 relative to the attachment assembly 100 about theroll pivot axis 114. Other suitable motors could be used in otherembodiments.

Referring to FIGS. 5 and 6, the attachment assembly 100 further has aleading tracking adjusting actuator 150 l operatively connected betweenforwardly projecting tabs 152 l of the yoke 120 and forwardly projectingtabs 154 l of the plate 130, and a trailing tracking adjusting actuator150 t operatively connected between rearwardly projecting tabs 152 t ofthe yoke 120 and rearwardly projecting tabs 154 t of the plate 130. Theleading and trailing tracking adjusting actuators 150 l, 150 t are thuslongitudinally offset of the pivot axis 118.

Referring to FIG. 5, retraction of the actuator 150 l and extension ofthe actuator 150 t cause pivoting of the track system 40 about the pivotaxis 128 so as to adopt a toe-in angle −γ (i.e. the leading idler wheelassembly 400 l is pivoted inwards and towards the chassis 62 of thevehicle 60) relative to a plane 190, which extends parallel to alongitudinal direction of the track system 40, parallel to the centerplane 66 of the vehicle 60 and parallel to a height direction of thetrack system 40. Referring to FIG. 6, extension of the actuator 150 land retraction of the actuator 150 t cause pivoting of the track system40 about the pivot axis 128 so as to adopt a toe-out angle γ (i.e. theleading idler wheel assembly 400 l is pivoted outwards and away from thechassis 62 of the vehicle 60) relative to the plane 190.

In some embodiments, the actuators 150 l, 150 t can provide for trackingangle adjustment of up to about 10 degrees, that is angle γ equals toabout 10 degrees, but larger or smaller angles γ are contemplated indifferent embodiments. The degree of freedom in yaw motion about thepivot axis 128 permits the track systems 40, 40′ to adjust the trackingangle and reduce wear of the endless track 600 in some conditions due toa misalignment of the track systems 40, 40′. Like the camber angle θ,the toe-in/toe-out angle γ can be dynamically changed using theactuators 150 l, 150 t when required, depending on, for example,temperature of certain portions of the endless track 600, ground surfaceconditions and the load L of the vehicle 60. As such, premature wear ofthe endless track 600 and other components of the track system 40 isreduced compared to conventional track systems. Furthermore, asmentioned above, the selection of the toe-in/toe-out angle γ may alsoassist in preserving the integrity of the soil.

In addition, in another embodiment, the actuator 140 is omitted and thecamber angle θ is adjustable by simultaneously retracting or extendingthe actuators 150 l, 150 t. For example, in such an embodiment,simultaneously extending the actuators 150 l, 150 t causes the tracksystem 40 to adopt a negative camber angle −θ. Conversely, retractingthe actuators 150 l, 150 t causes the track system 40 to adopt apositive camber angle θ. Thus, in such an embodiment, the actuators 150l, 150 t are operable for selectively adjusting both the camber angle θand the toe-in/toe-out angle γ of the track system 40.

Moreover, when the track systems 40 is steerable, for example whenoperatively connected to a steerable component of the chassis 62, theactuators 150 l, 150 t could be operatively connected to the steeringsystem of the vehicle 60 so as to provide better steering control undersome circumstances. For example, when the vehicle 60 is steered to theright, the actuator 150 l is extended and the actuator 150 t isretracted so as to assist the track system 40 to steer the vehicle 60 tothe right.

Referring back to FIG. 2, a stop 160 projects inwardly from the leadingframe member 210 l and extends through an aperture 162 (seen in FIG.10B) defined in the plate 130. In the present embodiment, the stop 160is integrally formed with the leading frame member 210 l, but they couldbe provided as separate components connected together in anotherembodiment. The stop 160 is structured and dimensioned to limit thepivotal motion of the leading frame member 210 l about the pitch pivotaxis 118. In some embodiments, the aperture 162 is arcuate and thecenter of the arc of the aperture 162 coincides with the pitch pivotaxis 118. The stop 160 and/or the aperture 162 could be configuredotherwise and limit the pivotal motion of the leading frame member 210 lrelative to the plate 130 to a lesser or greater extent than the oneillustrated.

Leading and Trailing Frame Members

Referring now to FIGS. 3A to 8, the leading and trailing frame members210 l, 210 t will be described. The leading and trailing frame members210 l, 210 t are pivotably connected to the attachment assembly 100 asthey are supported by the pivot 116. The leading and trailing framemembers 210 l, 210 t are disposed laterally outwardly from theattachment assembly 100 (FIGS. 5 and 6). In order to facilitate thepivoting of the leading and trailing frame members 210 l, 210 t on thepivot 116, bearings (not shown) are disposed between the pivot 116 andeach frame member 210 l, 210 t. In some embodiments, bushings or tapperrollers could be used in place of bearings.

In the present embodiment, the leading and trailing frame members 210 l,210 t have apertures defined by loops 214 l, 214 t (FIG. 5). The pivot116 extends through the apertures of the loops 214 l, 214 t similar to apin in a hinge assembly, and provides for pivotable connection of theleading and trailing frame members 210 l, 210 t about the pitch pivotaxis 118. On the outwards side of the sprocket wheel 550, the damper 300interconnects an upper portion 220 l of the leading frame member 210 land an upper portion 220 t of the trailing frame member 210 t. Thedamper 300 controls the pivot motion about the pitch pivot axis 118 ofthe leading and trailing frame members 210 l, 210 t one relative to theother. The damper 300 includes a hydro-pneumatic cylinder 302. In someembodiments, the damper 300 further includes a coil spring. In someembodiments, the damper 300 is replaced by a coil spring, an air springor a hydro-pneumatic spring. When the track system 40 supports theweight of the vehicle 60, damper 300 is deformed (i.e. compressed) andthe cylinder 302 provides for a dampened pivotal motion of the leadingand trailing frame members 210 l, 210 t relative to each other.

The positioning of the damper 300 between the upper portions 220 l, 220t of the leading and trailing frame members 210 l, 210 t respectively,allows for a relatively long stroke of the cylinder 302 of the damper300. As a result, the damping action of the damper 300 is generally morerefined than in conventional track systems where the stroke of a dampingcylinder is shorter. Such configuration provides for a smoother dampingaction of the damper 300 and may reduce the risks of fully compressingthe damper 300. Under certain conditions, vibrations that are due to theground surface on which the track system 40 travels and transferred tothe leading and trailing frame members 210 l, 210 t are dampened by thedamper 300. As described above, the stop 160 limits the pivotal motionof the leading frame member 210 l relative to the plate 130, and thepivotal motion of the trailing frame member 210 t is limited by thestroke of the cylinder 302.

In some embodiments, the damper 300 has variable damping characteristicsas described in commonly owned International Patent Application No.PCT/CA2016/050418, filed Apr. 11, 2016, entitled “Progressive DampingSystem for a Track System” and published as WO 2016/161527. The contentof this application is incorporated herein by reference in its entirety.

FIGS. 1, 11 and 13 illustrate different configurations of the tracksystem 40 when stationary and with each of the leading and trailingidler and support wheel assemblies 400 l, 400 t, 410 a, 410 b, 410 cpositioned for the endless track 600 to be in ground contact (i.e. theground engaging segment 620 extends from below the leading idler wheelassembly 400 l to below the trailing idler wheel assembly 400 t).Referring to FIG. 1, the track system 40 is shown in a restconfiguration. In this position, the track system 40 supports a nominalload. The nominal load of the track system 40 corresponds to the tracksystem 40 being attached to the vehicle 60 with the track system 40bearing its ordinary portion of the weight of the vehicle 60 when thevehicle 60 is at its tare weight, with no implements or attachments atthe front or rear and no payload in its container or tank. Referring toFIG. 11, the track system 40 is shown with the damper 300 fullyextended. Such configuration would be found when the track system 40supports a load that is smaller than the nominal load. In FIG. 13, thetrack system 40 is shown with the damper 300 fully compressed. Suchconfiguration would be found when the track system 40 supports a loadthat is greater than the nominal load.

Still referring to FIGS. 1, 11 and 13, the leading and trailing framemembers 210 l, 210 t of the track system 40 define a somewhatscissor-like structure, with each frame member 210 l, 210 t pivotingabout the pivot 116, and the damper 300 interconnected therebetween.Each one of the leading and trailing wheel-bearing members 230 l, 230 tis in turn pivotably connected to the leading and trailing frame member210 l, 210 t, respectively. The pivoting of each of these structures,along with the damper 300, may assist in reducing the verticaldisplacements and vibrations transferred from the track system 40 to thechassis 62 of the vehicle 60 under certain conditions.

In addition, having the track system 40 with such a scissor-likestructure has other advantages in certain situations. For example, asthe weight of the vehicle 60 increases, for example during harvesting orloading operations, the scissor-like structure can open and aground-contacting portion of the endless track 600 occurs over anincreased surface area (i.e. the ground engaging segment 620 increasesin size as the load borne by the track system 40 increases—at least forsome increases in load—depending on the design of a specific tracksystem). As a result, in some circumstances, the pressure applied to theground by the endless track 600 (owing to the weight and load of thevehicle 60) increases at a lower rate than the weight of the vehicle 60.In certain embodiments, this will allow the track system 40 to bearadditional loads as compared with conventional track systems.

Leading and Trailing Wheel-Bearing Frame Members and Idler Wheels

Referring to FIG. 7, in the illustrated embodiment of the presenttechnology, the leading wheel-bearing frame member 230 l is directlypivotably connected to the lower portion 222 l of the leading framemember 210 l and pivots about the axis 224 l. The leading idler wheelassembly 400 l is rotatably connected to the leading wheel-bearing framemember 230 l and rotates about an axis 404 l. A leading idler actuatorassembly 310 l is connected between the leading wheel-bearing framemember 230 l and the leading frame member 210 l for adjusting thepivotal positioning of the leading idler wheel assembly 400 l relativeto the leading frame member 210 l. When the leading idler actuatorassembly 310 l is retracted, as shown in FIG. 7, the leading idler wheelassembly 400 l pivots about the axis 224 l (in the counter-clockwisedirection in FIG. 7) and is pulled toward the leading frame member 210l. When the leading idler actuator assembly 310 l is retracted, theleading ground engaging segment 622 l extends above ground (when thetrack system 40 is disposed on flat level ground) as shown in FIG. 7. Insome circumstances, such as when the track system 40 has to travel overa bump or has to get out of a pothole or a ditch, raising the leadingidler wheel assembly 400 l may assist in overcoming the bump or gettingthe track system 40 out of the pothole or ditch. In addition, raisingthe leading idler wheel assembly 400 l using the actuator 310 l mayprevent undesirable soil compaction as the track system 40 gets out ofthe pothole or the ditch compared to conventional track systems wherethe leading idler wheel assembly 400 l would remain lowered. In thepresent embodiment, the leading idler actuator assembly 310 l alsolimits the pivotal motion and provides for a dampened pivotal motion ofthe leading wheel-bearing frame member 230 l and the leading framemember 210 l relative to each other about the axis 224 l.

Referring to FIG. 8, the trailing wheel-bearing frame member 230 t isdirectly pivotably connected to the lower portion 222 t of the trailingframe member 210 l and pivots about the axis 224 t. The trailing idlerwheel assembly 400 t is rotatably connected to the trailingwheel-bearing frame member 230 t and rotates about an axis 404 t. Atrailing idler actuator assembly 310 t is connected between the trailingwheel-bearing frame member 230 t and the trailing frame member 210 t foradjusting the pivotal positioning of the trailing idler wheel assembly400 t relative to the trailing frame member 210 t. When the trailingidler actuator assembly 310 t is retracted, as shown in FIG. 8, thetrailing idler wheel assembly 400 t pivots about the axis 224 t (in theclockwise direction in FIG. 8) and is pulled toward the trailing framemember 210 t. When the trailing idler actuator assembly 310 t isretracted, the trailing ground engaging segment 622 t extends aboveground (when the track system 40 is disposed on flat level ground) asshown in FIG. 8. In some circumstances, such as when the track system 40is travelling backwards over a bump or is getting out of a pothole or aditch, raising the trailing idler wheel assembly 400 t may assist inovercoming the bump or getting the track system 40 out of the pothole orthe ditch. In the present embodiment, the trailing idler actuatorassembly 310 t also limits the pivotal motion and provides for adampened pivotal motion of the trailing wheel-bearing frame member 230 tand the trailing frame member 210 t relative to each other.

It is also contemplated that, in some conditions, the idler actuatorassemblies 310 l, 310 t could be deactivated and configured to providefor an unbiased pivotal motion of their respective wheel-bearing framemember relative to their respective frame member.

In other embodiments, the actuator assemblies 310 l, 310 t could bereplaced by electric motors, such as stepper motors, or any othersuitable device operatively connected between the leading frame member210 l and the leading wheel-bearing frame member 230 l, and the trailingframe member 210 t and the trailing wheel-bearing frame member 230 t foradjusting the pivotal positioning therebetween.

Referring to FIGS. 7 to 10A, upon extension or retraction of theactuator assemblies 310 l, 310 t, the endless track 600 can selectivelyhave the leading ground-engaging segment 622 l and/or the trailingground engaging segment 622 t extending on or above the ground surface.Referring to FIG. 9, the track system 40 is shown travelling in theforward travel direction 80 over an uneven terrain T. When the leadingidler wheel assembly 400 l travels over a downwardly inclined surface Tland the support wheel assembly 410 a travels over a bump Tb, the leadingactuator assembly 310 l is passively or actively extended to maintain asmuch of the leading ground engaging segment 622 l as possible in contactwith the terrain T. As a result, the load born by the track system 40 isdistributed over a larger area than if the leading idler wheel assembly400 l were raised upon retraction of the actuator assembly 310 l.Similarly, as the trailing support wheel assemblies 410 b, 410 c and theidler wheel assembly 400 t travel in a recess Tr, the trailing idleractuator 310 t is passively or actively retracted to maintain as much ofthe trailing ground engaging segment 622 t as possible in contact withthe terrain T. As a result, the load born by the track system 40 isdistributed over a larger area than if the trailing idler wheel assembly400 t were lowered upon extension of the actuator assembly 310 t andpressure is thus more evenly distributed along the ground engagingsegment 620 of the endless track 600.

Referring to FIG. 10A, both the leading and trailing actuator assemblies310 l, 310 t are retracted and, as mentioned above, the ground engagingsegment 620 is shorter than in the configurations shown in FIG. 1, 7 or8. The configuration of FIG. 10A can assist in reducing wear of theendless track 600 when travelling over hard ground surfaces, such as apaved road. As the amount of endless track 600 in ground contact isreduced compared to the configurations shown in FIGS. 1, 7 and 8,rolling resistance of the track system 40 and/or wear of the endlesstrack 600 are reduced under some conditions. In addition, when theleading ground engaging segment 622 l extends above ground, an angle ofattack a of the endless track 600 when engaging the ground surface isreduced compared to the same angle of attack a in the configurationshown in FIG. 1 where the endless track 600 wraps around the leadingidler wheel assembly 400 l and contacts the ground. The angle of attacka of the endless track 600 shown in FIG. 7 may assist in reducing wearof the tread 608 under some conditions.

Moreover, steering of the track system 40 is facilitated when both theleading and trailing actuator assemblies 310 l, 310 t are retracted, andthe track system 40 has a behavior that is more akin to a wheel and tireassembly. Thus, under certain conditions such as when the track system40 travels over hard ground surfaces, configuring the track system 40 asshown in FIG. 10A is advantageous over the configuration shown in FIG. 1to reduce wear of the endless track 600.

Tensioner

Referring now to FIG. 10B, the leading wheel-bearing frame member 230 lincludes a tensioner 420 having first and second ends 422, 424respectively. The first end 422 extends inside a recess 423 of theleading wheel-bearing frame member 230 l and is rotatably connected tothe leading wheel-bearing frame member 230 l at a proximal tensioningpivot 426. A wheel linkage 428 is rotatably connected to the leadingwheel-bearing frame member 230 l at an axis 430 (shown as a dashed linein FIG. 10B) that is offset from the axis 404 l. The second end 424 ofthe tensioner 420 is rotatably connected to the wheel linkage 428 at adistal tensioning pivot 432 which is offset from the axis 404 l. Aleading axle assembly 440 l is operatively connected to the wheellinkage 428 and defines the axis 404 l. The distal tensioning pivot 432and the axis 430 are angularly displaced around the axis 404 l such thatthe wheel linkage 428 forms a lever with the axis 430 being the fulcrumthereof.

The action of the tensioner 420 and the wheel linkage 428 bias theleading axle assembly 440 l forward, and thus the leading idler wheelassembly 400 l is biased toward the forward end of the track system 40with a biasing force 701 (FIGS. 15 and 16). The endless track 600opposes the biasing force 701 provided by the action of the tensioner420 and the wheel linkage 428. Tensions 702, 704 (FIGS. 15 and 16)appear in the leading segment 610 and the leading ground-engagingsegment 622 l of the endless track 600.

In some embodiments, the tensioner 420 is used to reduce the variationsin the perimeter of the endless track 600 due to the pivoting of theleading and trailing frame members 210 l, 210 t respectively and leadingand trailing wheel-bearing frame members 230 l, 230 t respectively. Insome embodiments, the tensioner 420 is also operatively connected to theleading idler actuator assembly 310 l and/or the trailing idler actuatorassembly 310 t. When operatively interconnected, for example using ashared hydraulic system, the leading and trailing idler actuatorassemblies 310 l, 310 t and the tensioner 420 are operated incollaborative, synergistic fashion so as to reduce the variations in theperimeter of the endless track 600 and to prevent damage to the endlesstrack 600 and/or any one of the actuator assemblies 310 l, 310 t and thetensioner 420. In addition and referring to FIG. 9, the tensioner 420and the leading and trailing idler actuator assemblies 310 l, 310 t canbe operated in collaborative, synergistic fashion so as to maintain asmuch of the ground engaging segment 620 as possible in contact with theterrain T while maintaining adequate tension in the endless track 600.This is particularly useful when the terrain T and the bump Tb issensitive to soil compaction issues. Should the terrain T be a hardground surface not sensitive to soil compaction issues, the leading andtrailing idler actuator assemblies 310 l, 310 t and the tensioner 420could be operated in collaboration so as to increase the tension in theendless track to maximum operational tension so that the endless track600 extends rigidly above the recess Tr (i.e. without conforming to it)and over the bump Tb.

In addition, under certain conditions, if debris becomes stuck betweenone of the wheel assemblies and the endless track 600, the tensioner 420is configured to apply less biasing force 701 and/or retract so as toreduce variation in the perimeter of the endless track 600. When debrisare ejected from the track system 40, the tensioner 420 is configured toapply more biasing force 701 and/or extend to provide for adequatetension forces 702, 704 in the endless track 600. In addition, thetensioner 420 can be operated so as to increase tension in the endlesstrack 600 in some circumstances, such as during a hard braking event. Anincreased tension in the endless track 600 may reduce the risks of lugs604 of the endless track 600 skipping on the sprocket wheel 550.

In some embodiments, the tensioner 420 is a dynamic tensioning device asdescribed in commonly owned International Patent Application No.PCT/CA2016/050419, filed Apr. 11, 2016, entitled “Dynamic TensionerLocking Device for a Track System and Method Thereof”, and published asWO 2016/161528. The content of this application is incorporated hereinby reference in its entirety.

Support Wheel Assemblies

Referring to FIGS. 15 and 16, the support wheel assembly 410 a isrotatably connected to the leading wheel-bearing frame member 230 l androtates about an axis 412 a. The support wheel assemblies 410 b, 410 care rotatably connected to the trailing support wheel assembly 250 androtate about axes 412 b, 412 c respectively. The trailing support wheelassembly 250 has a body that is longitudinally elongated and thatextends above the lugs 604 of the endless track 600 (the lugs 604 areshown in FIG. 18). The trailing support wheel assembly 250 pivots aboutthe axis 252 with respect to the trailing wheel-bearing frame member 230t. As such, the support wheel assemblies 410 b, 410 c are indirectlypivotably connected to the trailing wheel-bearing frame member 230 t.

Material and Manufacturing

The various components of the track system 40 are made of conventionalmaterials (e.g. metals and metal alloys in most cases, such as steel)via conventional manufacturing processes (e.g. casting, molding, etc.).The present technology merely requires that each component be suitablefor the purpose for which it is intended and the use to which it is tobe put. Any material(s) or method(s) of manufacture which produce suchcomponents may be used in the present technology.

Lines and Resultant Forces

FIGS. 15 and 16 illustrate the track system 40 in a plane view that isparallel to the plane 190 (FIGS. 5 and 6). The pivot axis 118 and theaxes 224 l, 224 t, 252, 404 l, 404 t, 412 a, 412 b, 412 c areperpendicular to the plane 190 and are represented by “+” signs. Thepivot axis 118 and the axis 224 l are spaced apart by a longitudinaldistance 800 a defined in the plane 190. The pivot axis 118 and the axis224 t are spaced apart by a longitudinal distance 800 b defined in theplane 190. In this embodiment, the longitudinal distance 800 a isgreater than the longitudinal distance 800 b. As a result, the leadingframe member 210 l defines a lever arm between the pivot axis 118 andthe axis 224 l that is greater than the lever arm defined by thetrailing frame member 210 t between the pivot axis 118 and the axis 224t. As a portion of the weight of the vehicle 60 is transferred from thechassis 62 to track system 40 via the attachment assembly 100 and to thepivot 116, and in turn to the leading and trailing frame members 210 l,210 t, the trailing frame member 210 t supports a greater load than theleading frame member 210 l since the lever arm defined by the trailingframe member 210 t between the pivot axis 118 and the axis 224 t isshorter. To support the additional load on the trailing frame member 210t and in order to more evenly distribute the weight of the vehicle 60over the endless track 600, the trailing wheel-bearing frame member 230t has more support wheel assemblies indirectly rotatably connectedthereto than the leading wheel-bearing frame member 230 l (namely thesupport wheel assemblies 410 b, 410 c rotatably connected to thetrailing support wheel assembly 250).

The axes 412 a, 224 l are spaced apart in a longitudinal direction by alongitudinal distance 820 a defined in the plane 190. The axes 224 l,404 l are spaced apart in a longitudinal direction by a longitudinaldistance 830 a defined in the plane 190. In this embodiment, thedistance 820 a is shorter than the distance 830 a. A portion of theweight of the vehicle 60 is transferred at the axis 224 l from theleading frame member 210 l to the leading wheel-bearing member 230 l.Since the lever arm defined by the portion of the leading wheel-bearingmember 230 l supporting the leading support wheel assembly 410 a isshorter than the portion of leading wheel-bearing member 230 lsupporting the leading idler wheel assembly 400 l, the leading supportwheel assembly 410 a supports more load than the leading idler wheelassembly 400 l.

The axes 224 t, 252 are spaced apart in a longitudinal direction by alongitudinal distance 820 b defined in the plane 190. The axes 224 t,404 t are spaced apart in a longitudinal direction by a longitudinaldistance 830 b defined in the plane 190. In this embodiment, thedistance 820 b is shorter than the distance 830 b. A portion of theweight of the vehicle 60 is transferred at the axis 224 t from thetrailing frame member 210 t to the trailing wheel-bearing member 230 t.Since the lever arm defined by the portion of the trailing wheel-bearingmember 230 t supporting the trailing support wheel assembly 250 isshorter than the portion of the trailing wheel-bearing member 230 tsupporting the trailing idler wheel assembly 400 t, the trailing supportwheel assembly 250 and the support wheel assemblies 410 b, 410 c supportmore load than the trailing idler wheel assembly 400 t.

The axes 252, 412 b are spaced apart in a longitudinal direction by alongitudinal distance 840 b defined in the plane 190. Similarly, theaxes 252, 412 c are spaced apart in a longitudinal direction by alongitudinal distance 840 c defined in the plane 190. In thisembodiment, the distances 840 b, 840 c are equal. As such, the trailingsupport wheel assemblies 410 b, 410 c support equal loads.

By using the teachings in the present description and by selecting thedimensions of the various components described herein, a designer oftrack systems is able to set a distribution of load applied to theendless track 600 by the leading and trailing idler wheel assemblies 400l, 400 t and the support wheel assemblies 410 a, 410 b, 410 c to meetthe requirements of a particular application, the track system 40 beingin any one of the configurations shown in the accompanying Figures.

In the present embodiment, the distances 800 a, 800 b, 820 a, 820 b, 830a, 830 b, 840 b, 840 c, the diameter and width of the idler and supportwheel assemblies 400 t, 410 a, 410 b, 410 c are selected to distributeequally or close to equally the pressure applied to the endless track600 by the leading support wheel assembly 410 a, the trailing supportwheel assemblies 410 b, 410 c and the trailing idler wheel assembly 400t. In this embodiment, the pressure applied to the endless track 600 bythe leading idler wheel assembly 400 l is less than the pressure appliedby each one of the leading support wheel assembly 410 a, the trailingsupport wheel assemblies 410 b, 410 c and the trailing idler wheelassembly 400 t, at least when the leading idler actuator assembly 310 lis not actively extended.

Other configurations in other embodiments are contemplated. Forinstance, the distances 800 a, 800 b, 820 a, 820 b, 830 a, 830 b, 840 b,840 c, the diameter, width, cross-sectional profile and structure of theidler and support wheel assemblies 400 l, 400 t, 410 a, 410 b, 410 ccould be selected to equalize the pressure applied to the endless track600 by the support wheel assemblies 410 a, 410 b, 410 c. In yet otherembodiments, the distances 800 a, 800 b, 820 a, 820 b, 830 a, 830 b, 840b, 840 c, the diameter and width of the idler and support wheelassemblies 400 l, 400 t, 410 a, 410 b, 410 c could be selected toequalize the pressure applied to the endless track 600 by the leadingand trailing idler wheel assemblies 400 l, 400 t.

Note that in the accompanying Figures, the arrows indicating the tensionforces, torques and biasing force are not to scale, they are schematic.Referring to FIGS. 15 and 16 and as described above, the combinedactions of the tensioner 420 and the wheel linkage 428 (shown in FIG.10B) on the leading idler wheel assembly 400 l generate a biasing force701 at the axis 404 l. As a result, opposed tension forces 702, 704exist in the leading and ground engaging segments 610, 620 of theendless track 600. A resultant force 710 (e.g. the combination oftension forces 702, 704) is applied to the leading idler wheel assembly400 l at the axis 404 l and opposes biasing force 701. The leading andground engaging segments 600, 620 of the endless track 600 form an angle700 a. The resultant force 710 is colinear with a bisector 702 a of theangle 700 a.

The leading wheel-bearing frame member 230 l carries the resultant force710 to the axis 224 l along a line 750 a extending between the axis 404l and the axis 224 l, the line 750 a being shown as a dashed line inFIGS. 15 and 16. In FIG. 15, the line 750 a is colinear with thebisector 702 a, but it could be otherwise in other embodiments as otherconfigurations of the leading wheel bearing frame member 230 l arecontemplated. Having the resultant force 710 passing through the axis224 l has the effect of preventing the generation of a torque that isapplied to the leading wheel-bearing member 230 l about the axis 224 l.The line 750 a and the bisector 702 a extend above the pivot axis 118.As the resultant force 710 is applied along the bisector 702 a, theresultant force 710 passes above the pivot axis 118. Having theresultant force 710 passing above the pivot axis 118 has the effect ofgenerating a torque 740 a that is applied to the leading frame member210 l about the pitch pivot axis 118, inducing a rotation in acounter-clockwise direction referring to FIG. 15. The torque 740 a alsohas the effect of decreasing the load supported by the leading idlerwheel assembly 400 l, and increasing the load supported by the supportwheel assemblies 410 b, 410 c and the trailing idler wheel assembly 400t. The load applied to the leading idler wheel assembly 400 l can beincreased by actively extending the leading idler actuator assembly 310l. As such, the load applied to the endless track 600 by the leadingidler wheel assembly 400 l and the leading support wheel assembly 410 adepends at least in part on the biasing force 701 applied by thetensioner assembly 420 and the actuation force exerted by the leadingactuator assembly 310 l.

To oppose the tension forces 704, equally opposed tension forces 720 areapplied on the ground-engaging segment 620 of the endless track 600proximate to the trailing idler wheel assembly 400 t. Tension forces 722also appear in the trailing segment 630 of the endless track 600 andoppose tension forces 724, 726 appearing in the endless track 600adjacent to the sprocket wheel 550. In FIGS. 15 and 16, tension forces702, 704, 720, 722, 724, 726 are equal in magnitude (when the tracksystem 40 is static and without friction). A resultant force 730 (e.g.the combination of tension forces 720, 722) is applied to the trailingidler wheel assembly 400 t and the resultant force 730 is applied at theaxis 404 t.

The trailing and ground engaging segments 630, 620 of the endless track600 form an angle 700 b. The resultant force 730 is colinear with abisector 702 b of the angle 700 b in FIG. 15. The trailing wheel-bearingframe member 230 t carries the resultant force 730 to the axis 224 talong a line 750 b extending between the axis 404 t and the axis 224 t,shown as a dashed line in FIGS. 15 and 16. In FIG. 15, the line 750 b iscolinear with the bisector 702 b, but it could be otherwise in otherembodiments as other configurations of the trailing wheel bearing framemember 230 t are contemplated. Having the resultant force 730 passingthrough the axis 224 t has the effect of preventing the generation of atorque that is applied to the trailing wheel-bearing member 230 t aboutthe axis 224 t. The line 750 b and the bisector 702 b pass below thepitch pivot axis 118. As the resultant force 730 is applied along thebisector 702 b in FIG. 15, the resultant force 730 passes below thepivot axis 118, and a torque 740 b is applied to the trailing framemember 210 t about the pivot axis 118. From the perspective of FIG. 15,the torque 740 b has the effect of inducing a counter-clockwise rotationof the trailing frame member 210 t about the pitch pivot axis 118. Thetorque 740 b also has the effect of increasing the load supported by thesupport wheel assemblies 410 b, 410 c and the load supported by thetrailing idler wheel assembly 400 t. The torque 740 b also has theeffect of decreasing the load supported by the leading idler wheelassembly 400 l and the leading support wheel assembly 410 a.

In the present embodiment, the magnitude of the force 730 is equal tothe resultant force 710, but the magnitude of the torque 740 b isgreater than that of the torque 740 a. A net torque 760 is applied tothe track system 40 in the same direction as torques 740 a, 740 b, inthe counter-clockwise direction when referring to FIGS. 15 and 16. Thedamper 300 limits the pivotal motion of the leading and trailing framemembers 210 l, 210 t about the pivot axis 118 and the net torque 760 hasthe effect of decreasing the load supported by the leading idler wheelassembly 400 l and the support wheel assembly 410 a.

When the track system 40 is driven, additional tension forces appear inthe endless track 600 because of the tractive forces applied by thesprocket wheel 550 to the endless track 600. As such, the magnitude oftension forces 724, 722 and 720 increases. Simultaneously, the tensioner420 is configured to increase its biasing force 701 and maintainadequate tension forces 702, 704 in the endless track 600. Theseadditional tension forces make the magnitude of the resultant force 730greater when the track system 40 is driven, and the magnitude of theresultant force 730 becomes greater than the magnitude of the resultantforce 710.

When the track system 40 is driven, the load applied to the endlesstrack 600 (and hence pressure applied to the ground surface) under theleading idler wheel assembly 400 l and leading support wheel assembly410 a are decreased, and the pressures applied to the endless track 600under the support wheel assemblies 410 b, 410 c and trailing idler wheelassembly 400 t are increased. As a result, in some conditions, the tracksystem 40 has a reduced tendency to pitch negatively, especially whendriven on soft grounds. This tendency can be modulated by activelyextending the leading idler actuator assembly 310 l, if needed.

Moreover, under certain conditions, heat generation and wear of theouter surface 606 (FIG. 1) of the endless track 600 are reduced whencomparing the track system 40 to conventional track systems attached tothe same vehicle 60 for the following reasons. First, as there is areduced load applied under the leading idler wheel assembly 400 l, thereis a reduced pressure applied to the endless track 600 as it engages theground. The tread 608 has improved engagement with the ground beforebeing parallel thereto and being subjected to tractive forces. Second,as the weight of the vehicle 60 increases, the surface area of theendless track 600 in contact with the ground increases due to thescissor-like structure of the track system 40. Thus, as mentioned above,the pressure on the ground increases at a rate that is less than therate of increase in weight of the vehicle 60.

Referring to FIG. 16 where the leading and trailing idler actuators 310l, 310 t are retracted, the same lines, forces and torques as describedin reference to FIG. 15 are reproduced. The leading idler actuatorassembly 310 l limits the pivotal motion between the leading wheelbearing frame member 230 l and the leading frame member 210 l. Theleading wheel-bearing frame member 230 l carries the force 710 along theline 750 a, which is not colinear with the bisector 702 a. As the line750 a passes through the axis 224 l and the pitch pivot axis 118, theforce 710 has the effect of inducing no torque 740 a to the leadingframe member 210 l about the pivot axis 118.

The trailing idler actuator assembly 310 t limits the pivotal motionbetween the trailing wheel bearing frame member 230 t and the trailingframe member 210 t. The trailing wheel-bearing frame member 230 tcarries the force 730 along the line 750 b, which is not colinear withthe bisector 702 b. The line 750 b passes through the axis 224 t andbelow the pitch pivot axis 118, and is further below the pitch pivotaxis 118 than the line 750 b found in the configuration of FIG. 15. Fromthe perspective of FIG. 16, the torque 740 b has the effect of inducinga counter-clockwise rotation of the trailing frame member 210 t aboutthe pitch pivot axis 118. The magnitude of the torque 740 b in theconfiguration of FIG. 16 is greater than in the configuration of FIG.15. The torque 740 b also has the effect of increasing the loadsupported by the support wheel assemblies 410 b, 410 c and the loadsupported by the trailing idler wheel assembly 400 t while decreasingthe load supported by the support wheel assembly 410 a and the leadingidler wheel assembly 400 l.

Thus, referring to the configuration shown FIG. 16, the net torque 760has the effect of reducing the tendency of the track system 40 to pitchnegatively, and combined with having the leading ground engaging segment622 l extending above the ground engaging segment 620, the track system40 has a configuration that makes it more capable of driving itself outof a ditch, a pothole or to overcome an obstacle, especially whentravelling on a soft ground surface.

In summary, the leading and trailing idler actuators 310 l, 310 t can beselectively actuated depending on the ground conditions, whether it isto drive the track system 40 out of a ditch, a pothole or to overcome anobstacle, or to distribute more evenly the load on the endless track 600when travelling on ground which is sensitive to soil compaction issues.

In addition to the reduced tendency of the track system 40 to pitchnegatively, when the track system 40 encounters an obstacle such as abump or a depression along its path of travel, the pivoting of theleading and trailing wheel-bearing members 230 l, 230 t, and of theleading and trailing frame members 210 l, 210 t has the effect ofreducing vertical displacements and vertical acceleration of the pivot116. Accordingly, vertical displacements and vertical accelerations ofthe chassis 62 of the vehicle 60 are reduced. Notably, at certain speedregimes, the pivoting of the leading and trailing wheel-bearing members230 l, 230 t alone is sufficient to reduce the vertical displacements ofthe pivot 116. At other speed regimes, it is the combined action of thepivoting of the leading and trailing wheel-bearing members 230 l, 230 tand of the leading and trailing frame members 210 l, 210 t, and thedamping action of the damper 300 that reduce the vertical displacementsand vertical accelerations of the pivot 116.

Track System Controller and Monitoring Sensors

Referring to FIGS. 17A to 17C, the vehicle 60 is schematicallyrepresented with a track system 40, according to one embodiment of thepresent technology, operatively connected at each corner of the vehicle60. The forward travel direction 80 of the vehicle 60 is also indicated.The track system 40 is operatively connected to the vehicle 60 at thefront right corner, the track system 40′ is operatively connected to thevehicle 60 at the front left corner, a track system 40 r is operativelyconnected to the vehicle 60 at the rear right corner, and a track system40 r′ is operatively connected to the vehicle 60 at the rear leftcorner. A track system controller 1000, schematically represented by atriangle in FIGS. 17A to 17C, is operatively connected to each tracksystem 40, 40′, 40 r, 40 r′ and controls the operation of the actuatorassemblies 140, 150 l, 150 t, 310 l, 310 t, 420 for each track system40, 40′, 40 r and 40 r′. Each track system controller 1000 is powered bythe electrical system of the vehicle 60, and each of the actuatorassemblies 140, 150 l, 150 t, 310 l, 310 t, 420 for each track system40, 40′, 40 r and 40 r′ is operatively connected to a power source. Eachtrack system controller 1000 includes a memory and a processing unitcapable of receiving and sending signals. The dashed lines in FIG. 17Aindicate that the track system controllers 1000 are operativelyinterconnected to one another.

As will be described below, each track system controller 1000 controlsthe operation of the actuator assemblies 140, 150 l, 150 t, 310 l, 310t, 420 of its corresponding track system 40, 40′, 40 r, 40 r′ dependingon various input signals received from the operator of the vehicle 60and/or from a plurality of monitoring sensors 1100, schematicallyrepresented in FIGS. 17A to 17C as squares. As such, each track systemcontroller 1000 is programmable and capable of running predeterminedsequences and actions so as to control the operation of the actuatorassemblies 140, 150 l, 150 t, 310 l, 310 t, 420 its corresponding tracksystem 40, 40′, 40 r, 40 r′ automatically or using manual override inaccordance with a predetermined objective.

In the present embodiment, the monitoring sensors 1100 are mounted atvarious locations on the vehicle 60 and on each one of the track systems40, 40′, 40 r, 40 r′. As will be described below, the monitoring sensors1100 are used for determining at least indirectly a state of each one ofthe track systems 40, 40′, 40 r, 40 r′ and/or a condition of the groundsurface on which the vehicle 60 travels. It is to be understood that themonitoring sensors 1100 can be embedded within, affixed, mounted orconnected to any of the suitable components of the vehicle 60 and tracksystems 40, 40′, 40 r, 40 r′. The monitoring sensors 1100 may beoperatively connected to the track system controllers 1000 via wire orvia a wireless connection. The operative connection between themonitoring sensors 1100 and the track system controllers 1000 is shownby the dashed lines in FIGS. 17A to 17C.

In some embodiments, the monitoring sensors 1100 include temperaturesensors capable of determining the temperature of different componentsof the track systems 40, 40′, 40 r, 40 r′. For example, temperaturesensors can be embedded within or disposed proximate the endless tracks600, the idler and support wheel assemblies 400 l, 400 t, 410 a, 410 b,410 c and/or the actuator assemblies 140, 150 l, 150 t, 310 l, 310 t,420 for accurate temperature measurement of certain portions of eachcomponent. The temperature sensors could be thermal radiationthermometers, thermocouples, thermistors, or any other suitable type ofsensing device capable of sensing temperature. In an embodiment wherethe temperature sensors are embedded in the endless tracks 600, they aredisposed to determine the temperature at various locations on theendless track 600, for example on the inward and/or outward portions ofthe endless track 600, near or on the inner surface 602, near or on thedrive lugs 604 and/or near or on the outer surface 606 of the endlesstrack 600. The collected temperature data is sent as signals to thecorresponding track system controller 1000. After processing thetemperature data, the track system controller 1000 determines acorresponding output signal related to the actuation of any one of theactuator assemblies 140, 150 l, 150 t, 310 l, 310 t, 420 based on thesignals received from the temperature sensors. In addition, the tracksystem controller 1000 is operable to identify which temperature sensorsends a given signal based on a unique identifier associated with eachtemperature sensor.

For example, in order to reduce risks of damaging the endless tracks 600due to excessive heat generation as the endless tracks 600 are driven,the track system controller 1000 of the track system 40 operates eachone of the actuator assemblies 140, 150 l, 150 t, 310 l, 310 t, 420,alone or in combination, to correct the positioning of the frameassembly 200 and the idler and support wheel assemblies 400 l, 400 t,410 a, 410 b, 410 c relative to the chassis 62 and/or the groundsurface. In an illustrative scenario, the temperature sensors determinethat the inward portions of the endless track 600 have temperaturereadings that are higher than the temperature readings of the outwardportions of the endless track 600, and that the difference intemperature readings is above a predetermined threshold. Based on thesignals received from the temperature sensors, the system controller1000 sends a signal to extend or retract the actuator 140 so as toadjust the camber angle θ of the track system 40 in order to more evenlydistribute the load across the ground engaging segment 620 of theendless track 600. A more even load distribution across the groundengaging segment 620 may not only assist in reducing undesirable heatgeneration in certain portions of the endless tracks 600, but may alsoreduce soil compaction when driving on soft ground surface. As such, thetrack system 40 is capable of dynamically adjusting the camber angle θbased on data collected by the monitoring sensors 1100 and processed bythe track system controller 1000.

In another illustrative scenario, the inward portions of the endlesstrack 600 of the track system 40 have temperature readings that arehigher than the temperature readings of the outward portions of theendless track 600, and that the difference in temperature readings isabove a predetermined threshold. Based on the signals received from thetemperature sensors, the system controller 1000 of the track system 40sends a signal to extend or retract the actuators 150 l, 150 t so as toadjust the toe-in/toe-out angle γ of the track system 40. Properalignment of the endless track 600 relative to the chassis 62 of thevehicle 60 may also assist in reducing undesirable heat generation andpremature wear in certain portions of the endless track 600. As such,the track system 40 is also capable of dynamically adjusting thetoe-in/toe-out angle γ based on data collected by the monitoring sensors1100 and processed by the track system controller 1000.

In other embodiments, the monitoring sensors 1100 also include, inaddition or in replacement of the temperature sensors, load cells (e.g.load transducers). The load cells can be piezoelectric load cells,hydraulic load cells, pneumatic load cells, or any other suitable typeof cells capable of sensing a load applied thereto. In some embodiments,the load cells are provided at various locations on the vehicle 60 (asrepresented in FIGS. 17A to 17C), such as under the tank, container orcargo area, in order to monitor a payload of the vehicle 60 and todetermine the location of the centre of gravity of the vehicle 60. Inone scenario where the vehicle 60 travels on a laterally inclined groundsurface, the track system controllers 1000 collectively determine thelocation of the centre of gravity of the vehicle 60 using data receivedfrom the load cells located on the vehicle 60. The track systemcontrollers 1000 are then capable of sending signals to one another toextend or retract their corresponding actuator 140 so as to adjust thecamber angle θ of their corresponding track systems 40, 40′, 40 r, 40 r′in order to more evenly distribute the load across the ground engagingsegment 620 of each of the endless tracks 600. This is another exampleof the track system 40 being capable of dynamically adjusting the camberangle θ based on data collected by the monitoring sensors 1100 andprocessed by one or more of the track system controllers 1000.

In some embodiments, additional load cells are disposed in variouscomponents of each track system 40, 40′, 40 r, 40 r′. For example, inembodiments where load cells are embedded within the endless track 600in the inward and outward portions thereof, the load data of each loadcell is sent as signals to the corresponding track system controller1000. In situations where the inward portion of the endless track 600have load readings that are higher than the load readings of the outwardportions of the endless track 600, and that the difference in loadreadings is above a predetermined threshold, the system controller 1000sends a signal to extend or retract the actuator 140 so as to adjust thecamber angle θ of the corresponding track system 40, 40′, 40 r, 40 r′ inorder to more evenly distribute the load across the ground engagingsegment 620. This way, soil compaction issues could be reduced comparedto conventional track systems as the track system controllers 1000dynamically adjust the position of the track systems 40, 40′, 40 r, 40r′ relative to the chassis 62 of the vehicle 60 (i.e. adjusting thecamber angle θ and/or the toe-in/toe-out angle γ) so as to more evenlydistribute the load born by each track system across the ground engagingsegment 620 of its respective endless track 600.

In other embodiments where each damper 300 is also operatively connectedto its corresponding track system controller 1000, the load readingssent as signals by the load sensors located on the vehicle 60 to thetrack system controller 1000 also enable to dynamically adjust certainproperties of the damper 300, such as the damping ratio, as a functionof the load of the vehicle 60. As such, certain properties of the damper300 of each track system 40, 40′, 40 r, 40 r′ are dynamically modifieddepending on the load readings.

In yet other embodiments, the monitoring sensors 1100 also includestrain gauges. The strain gauges could be located, for example, at thepivot joints connecting the actuator assemblies 140, 150 l, 150 t, 310l, 310 t, 420 to the frame assembly 200, or at the pivot joints of theframe assembly 200. In an illustrative scenario, a strain gauge islocated at the pivot axis 224 l of the track system 40, the track system40 is initially in the configuration shown in FIG. 1, travels in theforward travel direction 80 and starts sinking down in a recess composedof soft soil. When a driving torque is applied to the sprocket wheel550, the strain gauge has a reading that is above a certain thresholdand sends a signal to the track system controller 1000. The track systemcontroller 1000 also receives a signal from the vehicle 60 that adriving torque is applied to the drive shaft 64 for turning the sprocketwheel 550 and that the speed of the vehicle 60 does not increase. Thetrack system controller 1000 sends a signal to retract the actuatorassemblies 310 l, 310 t so as to change the configuration of the tracksystem 40 from the one shown in FIG. 1 to the one shown for example inFIGS. 10A and 16. As described above, the configuration shown in FIGS.10A and 16 benefits from an increased torque 760 and the track system 40has a reduced tendency to pitch negatively, which can assist the tracksystem 40 to drive itself out of the recess where it might be otherwisebogged down should the track system 40 have remained in theconfiguration shown in FIG. 1.

In some embodiments, the monitoring sensors 1100 include accelerometers.The accelerometers could be located, for example, on the attachmentassembly 100 of each track system 40, 40′, 40 r, 40 r′. In such anembodiment, the accelerometers detect the vibrations that have not beendampened or not dampened to a sufficient amount by the track systems 40,40′, 40 r, 40 r′. The accelerometers measure the vertical accelerationto which the attachment assembly 100 is subjected and send this data assignals to the corresponding track system controller 1000. Uponreception of the vertical acceleration signals, the track systemcontroller 1000 processes this data and sends a signal to acabin-mounted suspension assembly 1200 schematically represented in FIG.18. The cabin-mounted suspension assembly 1200 is capable of moving theseat and/or the entire cabin that the operator occupies to subject it tovertical accelerations that have frequencies and amplitudes adapted tocancel out or reduce the vertical accelerations that the track systems40, 40′, 40 r, 40 r′ experience and that are conducted to the cabin. Asa result of the cooperation between the track systems 40, 40′, 40 r, 40r′ and the cabin-mounted suspension assembly 1200, an operator locatedin the cabin receives less vibrations from the track systems 40, 40′, 40r, 40 r′ and would therefore feel more comfortable than if the vehicle60 was equipped with conventional track systems.

In yet other embodiments, the accelerometers are capable of detectingvibrations in the proximity of various components of the track systems40, 40′, 40 r, 40 r′. Signals generated by the accelerometers are sentto the track system controller 1000 which determines over time the usageand wear of the components of the track systems 40, 40′, 40 r, 40 r′.This may be useful to obtain general information related to thecondition of various components of the track systems 40, 40′, 40 r, 40r′, perform an analysis of the frequencies of the acceleration dataand/or perform at the right time predictive maintenance operations toreduce risks of component failures. For example, the acceleration andvibration data related to bearings, pivot pins, seals and the gearbox500 could be analyzed in real time and/or populate a database that couldbe analyzed to determine early signs of excessive wear or failure ofcomponents of the track systems 40, 40′, 40 r, 40 r′.

In some embodiments, the monitoring sensors 1100 include inclinometers.The inclinometers could be located, for example, on the components ofthe frame assembly 200 and could be configured to send signals to thetrack system controller 1000 indicative of the camber angle θ of theaxle assemblies connecting the idler and support wheel assemblies 400 l,400 t, 410 a, 410 b, 410 c to the frame assembly 200 relative to theplane 190 (FIGS. 5 and 6). Similar to what has been described above, thesignals generated by the inclinometers are provided to the track systemcontroller 1000 which operates the actuator assembly 140 to adjust thepositioning of the frame assembly 200 and the idler and support wheelassemblies 400 l, 400 t, 410 a, 410 b, 410 c relative to the chassis 62and/or the ground surface in accordance with a predetermined objective.In some embodiments, the signals provided by the inclinometers could beused by the track system controller 1000 to assess and calibrate theoperation of the actuator assembly 140 and/or to assess the wear of thetread 606 of the endless track 600.

In some embodiments, the monitoring sensors 1100 include fluid propertysensors. The fluid property sensors could be located, for example,within the axle assemblies connecting the idler and support wheelassemblies 400 l, 400 t, 410 a, 410 b, 410 c to the frame assembly 200.The fluid property sensors assess various properties and characteristicsof the fluid contained within axle assemblies, such as viscosity,density, dielectric constant, temperature, presence of water, presenceof suspended contaminants and wear debris. The data collected from thefluid property sensors could assist the track system controller 1000 todetermine the condition and wear of some of the components of the tracksystems 40, 40′, 40 r, 40 r′.

In some embodiments, the monitoring sensors 1100 could include actuatorassembly position sensors. The actuator assembly position sensors couldinclude linear displacement transducers connected to one or more of theactuator assemblies 140, 150 l, 150 t, 310 l, 310 t, 420 that could sendsignals to the track system controller 1000 indicative of the positionand/or length of the corresponding actuator assembly 140, 150 l, 150 t,310 l, 310 t, 420. Using the signals provided by the linear displacementtransducers, the track system controller 1000 could assess the status ofextension/retraction of the actuator assemblies 140, 150 l, 150 t, 310l, 310 t, 420 and assist in determining how to operate them. Theactuator assembly position sensors could also include inclinometersconnected to, for example, the leading and trailing idler actuatorassemblies 310 l, 310 t. Using references and baselines, theinclinometers could send signals to the track system controller 1000indicative of the position and/or length of the corresponding actuatorassembly 310 l, 310 t. These signals could also assist the track systemcontroller 1000 to assess the status of extension/retraction of theactuator assemblies 310 l, 310 t and assist in determining how tooperate them.

In some embodiments, the monitoring sensors 1100 include positionsensors capable of assessing a geographical location of each one of thetrack systems 40, 40′, 40 r, 40 r′. The assessment of the geographicallocation may be useful for the track system controllers 1000 which couldrecord data related to, for example, strain at pivot joints and verticalacceleration to which the track systems 40, 40′, 40 r, 40 r′ aresubjected in conjunction with the geographical location. Externalsources of information could also be stored in the memory of the tracksystem controllers 1000, such as detailed road plans, topography dataand agricultural field terrain data. As such, in some embodiments, thetrack system controller 1000 learns optimal configurations of each ofthe track systems 40, 40′, 40 r, 40 r′ for each particular geographiclocation of the vehicle. In some embodiments, the track systemcontroller 1000 is configured to prime and/or configure in real-time theactuator assemblies 140, 150 l, 150 t, 310 l, 310 t, 420 so that each ofthe track systems 40, 40′, 40 r, 40 r′ has the more appropriateconfiguration for the ground surface on which it travels. In someembodiments, the track system controller 1000 is configured to prime thetrack systems 40, 40′, 40 r, 40 r′ for each given geographical locationby adjusting one or more of the actuator assemblies 140, 150 l, 150 t,310 l, 310 t, 420 thereof just before the track systems 40, 40′, 40 r,40 r′ reach each given geographical location. In some cases, and forsome types of terrain, this allows the track system controller 1000 todistribute the vehicle's weight relatively more evenly across the tracksystems 40, 40′, 40 r, 40 r′ and/or more evenly into the terrain acrosseach ground engaging segment 620 of each of the endless tracks 600 ofeach of the track systems 40, 40′, 40 r, 40 r′. In some cases, and forsome types of terrain, this allows to reduce soil compaction. In otherwords, in embodiments where the monitoring sensors 1100 include positionsensors, the track systems 40, 40′, 40 r, 40 r′ become location-awaredevices and they are capable of adapting their configurationaccordingly. In some embodiments, the monitoring sensors 1100 do notinclude position sensors and the tack system controller 1000 receivesthe geographical location of the vehicle 60 that is provided by aposition sensor (such as a GPS device) of the vehicle 60.

For example, in a situation where the track system controller 1000determines that the geographical location of the track system 40corresponds to a paved road, the track system controller 1000 sends asignal to retract the actuator assemblies 310 l, 310 t so that the tracksystem 40 be configured as illustrated in FIG. 10A, for example. Inanother situation where the track system controller 1000 determines thatthe geographical location of the track system 40 corresponds to anagricultural field having soil sensitive to ground compaction, the tracksystem controller 1000 sends a signal to extend the actuator assemblies310 l, 310 t so as to distribute the load born by then track system 40over a greater ground engaging segment 620.

Moreover, as each of the track systems 40, 40′, 40 r, 40 r can have itsgeographical location monitored by the position sensors, the tracksystem controllers 1000 of the front-mounted track systems 40, 40′ arecapable of communicating with the track system controllers 1000 of therear-mounted track systems 40 r, 40 r′ so that they adjust theirconfiguration based on the data collected by the monitoring sensors 1100of the front-mounted track systems 40, 40′. In an illustrative scenario,the vehicle 60 travels in a straight line, the track systems 40, 40 rare initially in the configuration shown in FIG. 1 and the track system40 is driven into a pothole. The geographical location of that potholeis recorded by the track system controller 1000 of the track system 40and sent to the track system controller 1000 of the track system 40 r.The leading and trailing idler actuators 310 l, 310 t of the tracksystem 40 are retracted as shown in FIG. 10B so that the track system 40is configured to drive itself out of the pothole, as described above. Asthe vehicle 60 travels forward, the track system controller 1000 of thetrack system 40 r monitors the geographical location thereof and beforethe track system 40 r is driven in the same pothole, the track systemcontroller 1000 of the track system 40 r sends a signal to retract theleading and trailing idler actuators 310 l, 310 t of the track system 40r as shown in FIG. 10B. Thus, when the track system 40 r is driven intothe pothole, the track system 40 r is already configured so that drivingout of that same pothole is facilitated.

In some embodiments, the track system controller 1000 is configured toadjust the configuration of each of the track systems 40, 40′, 40 r, 40r based on the data collected by the monitoring sensors 1100 in time forthe track systems 40, 40′, 40 r, 40 r arriving at particular terrainconditions, such that the configuration of each of the track systems 40,40′, 40 r, 40 r is optimized for the particular terrain conditions. Inan illustrative scenario, the vehicle 60 at one point in time wastravelling at a given speed and a given direction monitored by the tracksystem controller 1000 and traveled over a pothole with the front righttrack system 40. At that time, the track system controller 1000 haddetected the existence and the geographic location of the pothole, andstored this data in its memory. The next time when the vehicle 60travels proximate the geographic location of the pothole, the tracksystem controller 1000 may determine that the vehicle 60 will drive overthe pothole again, but this time with its front left track system 40′.In such a case, the track system controller 1000 may determine aparticular time associated with the impending driving over the potholeby the front left track system 40′ using the geographic location of thefront left track system 40′ derived as described above, and the speedand direction of the vehicle 60. The track system controller 1000 maythen retract the leading idler actuator 310 l of the front left tracksystem 40′ just before the front left track system 40′ reaches thepothole, and may thereby reduce the impact that the front left tracksystem 40′ will experience upon entering the pothole. In someembodiments, the track system controller 1000 may also retract thetrailing idler actuator 310 t of the front left track system 40′. Insome cases this may assist the front left track system 40′ in drivingout of the pothole.

Once the front left track system 40′ exits the pothole, the track systemcontroller 1000 may extend the leading idler actuator 310 l and/or thetrailing idler actuator 310 t of the front left track system 40′ to the“pre-pothole” position(s). In some embodiments, the track systemcontroller 1000 is further configured to adjust the leading idleractuator 310 l and/or the trailing idler actuator 310 t while a givenone of the track systems 40, 40′, 40 r, 40 r′ is engaged with a potholeor other obstacle in order to improve traction.

In some embodiments, the monitoring sensors 1100 also include groundsurface sensors. The ground surface sensors can include devices such assonars, hygrometers, penetrometers, ultrasonic, microwave-based, radarand lidar devices capable of generating an accurate representation ofthe ground on which the vehicle 60 travels or is about to travel. Thesonars, hygrometers and penetrometers could provide data related to, forexample, composition of the soil, moisture content, air content, etc.,and the ultrasonic, microwave-based, radar and lidar devices couldprovide an accurate representation of the ground surface profile andpotential hazards. The data of the ground surface sensors is sent assignals to the track system controllers 1000 which then determine themore appropriate configuration of the track systems 40, 40′, 40 r, 40 r′based on the assessed representation of the ground surface. For example,in a situation where the ground surface sensors and the track systemcontrollers 1000 determine that the ground surface is relatively hardand bumpy, the track system controllers 1000 send signals to retract theactuator assemblies 310 l, 310 t to configure the track systems 40, 40′,40 r, 40 r′ in the configuration shown in FIG. 10A. In another situationwhere the ground surface sensors and the track system controllers 1000determine that the ground surface is relatively moist and soft andcomposed of loosely packed particles, the track system controllers 1000send signals to extend the actuator assemblies 310 l, 310 t to configurethe track systems 40, 40′, 40 r, 40 r′ in the configuration shown inFIG. 1.

Based on the above description, it is understood that in certainembodiments the monitoring sensors 1100 could include all of theabove-described sensors, and that in other embodiments, only a subset ofthe above-described sensors would be included. The monitoring sensors1100 could thus enable the track systems 40, 40′, 40 r, 40 r′ toanticipate the properties of the ground surface on which they are aboutto travel and/or anticipate obstacles to overcome, and permit themodification of the configuration of the track systems 40, 40′, 40 r, 40r′ accordingly.

As described above, the monitoring sensors 1100 are thus capable ofdetermining a state of the track system 40 and/or a ground surfacecondition of the ground on which the track system 40 travels.Determining a state of the track system 40 includes, and is not limitedto, (i) determining the temperature of different components and/orportions of the track system 40, (ii) determining the load supported bydifferent components and/or portions of the track system 40, (iii)determining the strain undergone by different components and/or portionsof the track system 40, (iv) determining the vibration undergone bydifferent components and/or portions of the track system 40, (v)determining wear of different components and/or portions of the tracksystem 40, (vi) determining the inclination of different componentsand/or portions of the track system 40, (vii) determining the status ofextension/retraction of the actuator assemblies 140, 150 l, 150 t, 310l, 310 t, 420, and (viii) determining the location of differentcomponents and/or portions of the track system 40. Determining a groundsurface condition of the ground on which the track system 40 travelsincludes, and is not limited to, (i) determining whether the groundsurface is a paved road or an agricultural field having soil sensitiveto ground compaction, (ii) determining the hazards and the profile ofthe ground surface, and (iii) determining at least one of a composition,a moisture content, and an air content of the soil.

In summary and as described in more details above, the track systemcontrollers 1000 and the monitoring sensors 1100 could assist in, amongother things, (i) planning predictive maintenance operations, (ii)recording relevant data related to the properties of the ground surfaceon which the track systems 40, 40′, 40 r, 40 r′ travel (for mappingpurposes for example), (iii) maintaining an appropriate tension in theendless tracks 600 depending on the properties of the ground surface,(iv) increase the comfort of the operator of the vehicle 60 should thevehicle 60 be equipped with a cabin mounted suspension assembly 1200operatively connected to one or more track systems 40, 40′, 40 r, 40 r′,(v) reducing soil compaction issues on sensitive ground surfaces, and(vi) improving traction of the endless track 600 of each of the tracksystems 40, 40′, 40 r, 40 r′.

Referring to FIG. 17B, a master control unit 1010 is provided on thevehicle 60 and operatively connected to control systems 61 of thevehicle 60. The track system controllers 1000 of the track systems 40,40′, 40 r, 40 r′ and at least some of the monitoring sensors 1100 areoperatively connected to the master control unit 1010. The mastercontrol unit 1010 includes a processing unit, a memory, is programmableand is configured to send and receive signals from/to the track systemcontrollers 1000 and the vehicle 60. As the master control unit 1010 issimultaneously operatively connected to the track system controllers1000 and to the vehicle 60, data provided by the control systems 61 ofthe vehicle 60 is taken into account by the master control unit 1010 andsupplemented to the signals received from the monitoring sensors 1100 soas to have a more complete representation of the status of the vehicle60 and track systems 40, 40′, 40 r, 40 r′.

In certain situations, the master control unit 1010 can override thetrack control systems 1000 in controlling the operation of the actuatorassemblies 140, 150 l, 150 t, 310 l, 310 t, 420 in accordance with apredetermined objective. In some circumstances, the master control unit1010 is connected to a remote network 1020 via a communication device1030, and data provided by the track system controllers 1000 and/or thecontrol systems 61 of the vehicle 60 are collected by the master controlunit 1010, uploaded to the remote network 1020 by the communicationdevice 1030 and processed by a remote processing unit 1040 using, insome instances, supplemental data related to, for example, weatherrecords, soil condition, etc. Processed data and/or control signals forthe track system controllers 1000 obtained from the remote processingunit 1040 are downloaded to the master control unit 1010 via the remotenetwork 1020 and communication device 1030 so that the master controlunit 1010 controls the track system controllers 1000 according to thisprocessed data and/or control signals.

Referring to FIG. 17C, the communication device 1030 is provided on thevehicle 60 and is operatively connected to the control systems 61 of thevehicle 60, to at least some of the monitoring sensors 1100 and to thetrack system controllers 1000 of the track systems 40, 40′, 40 r, 40 r′.The communication device 1030 is in operative communication with aremote master control unit 1050 which is at a remote location of thevehicle 60. As such, in this embodiment, the master control unit 1050 isnot onboard the vehicle 60 and thus, the processing of the data isperformed remotely. Processed data and/or control signals for the tracksystem controllers 1000 obtained from the master control unit 1050 arecommunicated to the communication device 1030 so that the track systemcontrollers 1000 is operated according to this processed data and/orcontrol signals.

Monitoring Sensors Connected to the Endless Track

Referring now to FIGS. 19 to 25, there will be described in more detailssome embodiments of the track system 40 having at least some of themonitoring sensors 1100 connected to the endless track 600. Themonitoring sensors 1100 may be connected, mounted, affixed, embedded orinstalled during the manufacturing of the endless track 600, and may beconnected, mounted, affixed, embedded or installed in such a way as toimpede or prevent removal. The monitoring sensors 1100 could also beconnected, mounted, affixed, embedded or installed after themanufacturing of the endless track 600 in such a way that permits theirremoval, servicing and replacement. More details regarding theconnection and arrangement of the monitoring sensors 1100 to the endlesstrack 600 are provided in the following description.

In the embodiment shown in FIGS. 19 to 22, the monitoring sensor 1100 isin the form of a compressible, flexible mat 1120 of electricallyresistive material with an array of sensing devices 1122 connected withelectrodes and provided on at least one of the main faces of the mat1120, i.e. the top face 1130 and the bottom face 1132. Herein the term“mat” is to be understood to encompass a film, a layer, a slide, amembrane, a fabric or a sheet made of plastic, polymer and/or syntheticmaterial, or a structured network. In the embodiment shown in FIGS. 19to 22, the sensing devices 1122 are only provided on the top face 1130of the mat 1120, i.e. the top face 1130 extending below the innersurface 602 of the endless track 600. The array of sensing devices 1122is arranged and configured to measure and output at least one physicalparameter prevailing in portions of the endless track 600. In otherembodiments, the mat 1120 includes piezoelectric materials. In someembodiments, the mat 1120 has a plurality of layers, in which it iscontemplated that some of the layers contain the sensing devices 1122,other layers protect or encapsulate the sensing devices 1122, and yetother layers provide structural integrity and resilience to the mat1120. It is also to be noted that in the accompanying Figures thethickness of the mat 1120 and size of the sensing devices 1122 are notscale.

In some embodiments, the sensing devices 1122 are made of polymericmaterials and are capable of measuring a variability of capacitance inat least one of the layers of the mat 1120 and/or the endless track 600.

As seen in FIGS. 19 to 22, the mat 1120 is flexible and resilient enoughso as to withstand deformations that the endless track 600 experiencesduring use, such as when it wraps around the leading and trailing idlerwheel assemblies 400 l, 400 t and the sprocket wheel 550. The mat 1120is embedded within the endless track 600. In some embodiments, the mat1120 is one of the plies of materials forming the endless track 600 andmay have additional materials therein for different reasons, such as forreinforcement. The mat 1120 is heat-resistant and can withstand themanufacturing process of the endless track 600 and the varyingtemperatures that the endless track 600 experiences during use. To powerthe mat 1120, an energy harvester 1140 (FIG. 21), such as a condenser, abattery, a piezoelectric device, or a thermoelectric device, is embeddedin one of the lugs 604 of the endless track 600 and electricallyconnected to the mat 1120. The energy harvester 1140 could also belocated elsewhere on the endless track 600 in other embodiments. Aprocessing and communicating unit 1150 is also embedded in one the lugs604 of the endless track 600. The processing and communicating unit 1150is operatively connected to the array of sensing devices 1122 and to theenergy harvester 1140. The processing and communicating unit 1150 isconfigured to generate signals indicative of the at least one physicalparameter prevailing in portions of the endless track 600 and measuredby the array of sensing devices 1122. The at least one physicalparameter relates to any one of temperature, pressure and mechanicalloading, acceleration, etc. as will be described below. The at least onephysical parameter is thus also indicative of a state of the tracksystem 40. The signals generated by the processing and communicatingunit 1150 are communicated to the track system controller 1000 of thetrack system 40 via a wireless connection. The connection could be wiredin some embodiments. In response to the signals indicative of the atleast one physical parameter prevailing in portions of the endless track600, the track system controller 1000 (FIGS. 17A to 17C), the mastercontrol unit 1010 (FIG. 17B) and/or the remote master control unit 1050(FIG. 17C) operate each one of the actuator assemblies 140, 150 l, 150t, 310 l, 310 t, 420, alone or in combination, so as to adjust thepositioning of the frame assembly 200 and the idler and support wheelassemblies 400 l, 400 t, 410 a, 410 b, 410 c relative to the chassis 62and/or the ground surface in accordance with a predetermined objective.

Referring to FIGS. 21 and 22, the mat 1120 extends over a majority of awidth 610 of the endless track 600. In addition, the mat 1120 extendsover the entire length 612 of the endless track 600. In otherembodiments, the mat 1120 could extend otherwise over the width 610 andlength 612 of the endless track 600. The mat 1120 could, for example,extend over a portion of the length 612 of the endless track 600, andnot the entire length 612. Furthermore, in other embodiments, the mat1120 is composed of several stripes or bands that extend transversallywithin the endless track 600. The stripes or bands could also extenddirectly below/above some of the features of the tread 608 of theendless track 600, and thus have a pattern that matches, at leastpartially, the one of the tread 608. As such, it is to be understoodthat the configuration, shape, orientation and position of the mat 1120can vary in other embodiments.

In the embodiment shown in FIGS. 21 and 22, the array of sensing devices1122 (schematically illustrated as dots on a grid in FIG. 22) is made ofrows 1124 and columns 1126. The rows 1124 extend along the width 610 ofthe endless track 610, and the columns 1126 extend along the length 612of the endless track 600. The amount of rows 1124 and columns 1126 andthe distance (i.e. pitch) therebetween defines a resolution of the mat1120. An increased amount of rows 1124 and/or columns 1126 (and thus areduced pitch in the longitudinal and transversal directions) provides ahigher resolution to the mat 1120 which provides a more accuraterepresentation of the at least one physical parameter prevailing inportions of the endless track 600 compared to endless tracks havingpunctual, scattered sensors. The effect of having a higher resolution ofsensing devices 1122 measuring the at least one physical parameterprevailing in portions of the endless track 600 synergistically enhancethe richness of the signals communicated to the track system controller1000, and thus the track system controller 1000, the master control unit1010 and/or the remote master control unit 1050 can operate each one ofthe actuator assemblies 140, 150 l, 150 t, 310 l, 310 t, 420, alone orin combination, so as to more precisely adjust the positioning of theframe assembly 200 and the idler and support wheel assemblies 400 l, 400t, 410 a, 410 b, 410 c relative to the chassis 62 and/or the groundsurface in accordance with a predetermined objective.

In the embodiment shown in FIGS. 23 to 25, the monitoring sensor 1100 isin the form of two flexible foils 1150 made of electrically resistivematerial with an array of sensing devices 1152 (schematicallyrepresented as dots in the accompanying FIGS. 24 and 25) provided on thetop face 1160 thereof. In other embodiments, the foils 1150 includepiezoelectric materials. Herein the term “foil” is to be understood toencompass a film, a layer, a slide, a membrane, filaments compacted intoa matrix to form a felt like material or a cloth, or a sheet made ofplastic, polymer and/or synthetic material. One foil 1150 is located onan inward portion 616 of the inner surface 602 of the endless track 600,and another foil 1150 is located on an outward portion of the innersurface 602 of the endless track 600. As such, the foils 1150 extend oneither side, laterally, of the lugs 604. As in the mat 1120 describedabove, the array of sensing devices 1152 in the foils 1150 is arrangedand structured to measure and read out at least one physical parameterprevailing in portions of the endless track 600. Again, it is to benoted that in the accompanying Figures the thickness of the foils 1150and size of the sensing devices 1152 are not scale. In some embodiments,the foils 1150 are composed of several stripes or bands that extendtransversally on the inner surface 602 of the endless track 600. Thestripes or bands could also extend directly below/above some of thefeatures of the tread 608 of the endless track 600, and thus have apattern that matches, at least partially, the one of the tread 608. Assuch, it is to be understood that the configuration, shape, orientationand position of the foils 1150 can vary in other embodiments.

In some embodiments, the foils 1150 may have several layers. In someembodiments, the sensing devices 1152 are made of polymeric materialsand are capable of measuring a variability of capacitance in at leastone of the layers of the foil 1150 and/or the endless track 600. In someembodiments, the foils 1150 have pressure sensitive property pressuresensitive capacitance. In some embodiments, each foil 1150 is aPyzoFlex™ foil, which is a printed piezoelectric pressure sensing foil.

Still referring to FIGS. 23 to 25, the foils 1150 are flexible andresilient enough so as to withstand deformations that the endless track600 experiences during use, such as when the endless track 600 wrapsaround the leading and trailing idler wheel assemblies 400 l, 400 t andthe sprocket wheel 550. The foils 1150 are connected to the innersurface 602 of the endless track 600 using any suitable bondingtechniques, such as using adhesives, or affixed by being vulcanized orlaminated to the inner surface 602 of the endless track 600 after themanufacturing thereof. In some embodiments, an interface material (notshown) is added between the inner surface 602 and the foils 1150 so asto, for example, enhance the securing of the foils 1150 to the endlesstrack 600, provide a play between the foils 1150 and the endless track600 and/or allow safe removal of the foils 1150 from the inner surface602. The foils 1150 are heat-resistant and can withstand the varyingtemperatures that the endless track 600 experiences during use. To powerthe foils 1150, an energy harvester 1170 (FIG. 24) such as a condenseror a battery is embedded in one of the lugs 604 of the endless track 600and electrically connected to the foils 1150. A processing andcommunicating unit 1180 is also embedded in one the lugs 604 of theendless track 600. The processing and communicating unit 1180 isoperatively connected to the array of sensing devices 1122 and to theenergy harvester 1170. The processing and communicating unit 1180 isconfigured to generate signals indicative of the at least one physicalparameter prevailing in portions of the endless track 600. The at leastone physical parameter relates to any one of temperature, pressure andmechanical loading, acceleration, etc. as will be described below. Thesignals generated by the processing and communicating unit 1180 arewirelessly communicated to the track system controller 1000 of the tracksystem 40. In other embodiments, the connection is wired. In response tothe signals indicative of the at least one physical parameter prevailingin portions of the endless track 600, the track system controller 1000,the master control unit 1010 and/or the remote master control unit 1050operate each one of the actuator assemblies 140, 150 l, 150 t, 310 l,310 t, 420, alone or in combination, so as to adjust the positioning ofthe frame assembly 200 and the idler and support wheel assemblies 400 l,400 t, 410 a, 410 b, 410 c relative to the chassis 62 and/or the groundsurface in accordance with a predetermined objective.

Referring to FIGS. 24 and 25, each foil 1150 extends over a minority ofthe width 610 of the endless track 600, but the foils 1150 extend overthe entire length 612 of the endless track 600. In other embodiments,the foils 1150 could extend otherwise over the width 610 and length 612of the endless track 600. The array of sensing devices 1152(schematically illustrated as dots in FIGS. 24 and 25) is made of rows1154 and columns 1156, the rows 1154 extending along the width 610 ofthe endless track 610 and the columns 1156 extending along the length612 of the endless track 600. It is contemplated that more or lesssensing devices 1152 could be used in different embodiments. The amountof rows 1154 and/or columns 1156 and the distance (i.e. pitch)therebetween defines the resolution of each foil 1150. An increasedamount of rows 1154 and/or columns 1156 (and thus a reduced pitch in thelongitudinal and transversal directions) provides a higher resolutionwhich provides a more accurate representation of the physical parametersprevailing in portions of the endless track 600 compared to endlesstracks having punctual, scattered sensors. The effect of having a higherresolution of sensing devices 1152 measuring the at least one physicalparameter prevailing in portions of the endless track 600synergistically enhance the richness of the signals communicated to thetrack system controller 1000, and thus the track system controller 1000,the master control unit 1010 and/or the remote master control unit 1050can operate each one of the actuator assemblies 140, 150 l, 150 t, 310l, 310 t, 420, alone or in combination, so as to more precisely adjustthe positioning of the frame assembly 200 and the idler and supportwheel assemblies 400 l, 400 t, 410 a, 410 b, 410 c relative to thechassis 62 and/or the ground surface in accordance with a predeterminedobjective.

In the embodiments shown in the accompanying Figures, the sensingdevices 1122, 1152 of the monitoring sensors 1100 are configured asstrain gauges. As the endless track 600 is deformed when the wheels ofthe idler and support wheel assemblies 400 l, 400 t, 410 a, 410 b, 410 croll thereon, the sensing devices 1122, 1152 are also deformed causingthem to emit a signal to the track system controller 1000 indicative ofa strain parameter. The strain parameter may be representative of aninstantaneous strain response, an average strain response over a periodof time, a peak strain response or any other suitable strain-relateddata. The strain parameter is thus indicative of a state of the tracksystem 40. As the properties of the endless track 600 are known, a loadparameter prevailing on the endless track 600 in regions correspondingto each one of the sensing devices 1122, 1152 can be estimated from thestrain parameter recorded by the sensing devices 1122, 1152. The loadparameter may be representative of an instantaneous load, an averageload supported over a period of time, a peak load or any other suitableload-related data. The load parameter is also indicative of a state ofthe track system 40

In some embodiments, the sensing devices 1122, 1152 of the monitoringsensors 1100 are arranged and configured as load cells. As the idler andsupport wheel assemblies 400 l, 400 t, 410 a, 410 b, 410 c roll on thesensing devices 1122, 1152 when the endless track 600 engages theground, the sensing devices 1122, 1152 record the load they aresubjected to and emit a signal to the track system controller 1000indicative of a load parameter prevailing on the endless track 600 inregions corresponding to each one of the sensing devices 1122, 1152. Theload parameter may be representative of an instantaneous load, anaverage load supported over a period of time, a peak load or any othersuitable load-related data.

In some embodiments, the estimation and/or measurement of the loadparameter is performed in conjunction with data from finite elementanalysis of endless track 600 that is stored in the memory of the tracksystem controller 1000, the master control unit 1010 and/or the remotemaster control unit 1050 and which takes into account the position andconfiguration of the sensing devices 1122, 1152. As a result, theestimation of the load parameter prevailing in regions of the endlesstrack 600 has improved accuracy.

In response to the signals indicative of the load parameter of each ofthe sensing devices 1122, 1152, the track system controller 1000, themaster control unit 1010 and/or the remote master control unit 1050operates each one of the actuator assemblies 140, 150 l, 150 t, 310 l,310 t, 420, alone or in combination, so as to adjust the positioning ofthe frame assembly 200 and the idler and support wheel assemblies 400 l,400 t, 410 a, 410 b, 410 c relative to the chassis 62 and/or the groundsurface in accordance with a predetermined objective, which can be incertain conditions to more evenly distribute the load across the groundengaging segment 622 of the endless track 600.

For example, in an illustrative scenario, the track system controller1000, the master control unit 1010 or the remote master control unit1050 receives and processes signals from the sensing devices 1122, 1152indicative that the load parameter supported by the endless track 600 onthe inward portion 616 thereof is greater than the load parametersupported by the outward portion 618 thereof, and that the differencebetween the load parameters is above a predetermined threshold. Thetrack system controller 1000, the master control unit 1010 and/or theremote master control unit 1050 operates the actuator assembly 140 so asto change the camber angle θ in accordance with the predeterminedobjective of, for example, more evenly distributing the load across theground engaging segment 622 of the endless track 600. The track systemcontroller 1000, the master control unit 1010 and/or the remote mastercontrol unit 1050 continues receiving and processing the signals fromthe strain gauges 1102, 1104 indicative of the load parameter supportedby the inward and outward portions 616, 618 of the endless track 600until the difference between the load parameters supported is below thepredetermined threshold.

In another illustrative scenario, the track system controller 1000, themaster control unit 1010 and/or the remote master control unit 1050receives and processes the signals indicative that the load parametermeasured/estimated by sensing devices 1122, 1152 located in the leadingground engaging segment 622 l is smaller than the load parametermeasured/estimated by the sensing devices 1122, 1152 located in thetrailing ground engaging segment 622 t and that the difference betweenthe load parameters is above a predetermined threshold. The track systemcontroller 1000, the master control unit 1010 and/or the remote mastercontrol unit 1050 operates the leading actuator assembly 310 l so as tolower the leading idler wheel assembly 400 l in accordance with thepredetermined objective of, for example, more evenly distributing theload across the ground engaging segment 622 of the endless track 600.The track system controller 1000, the master control unit 1010 and/orthe remote master control unit 1050 continues receiving and processingsignals from the monitoring sensors 1100 indicative of the loadparameters until the difference between the load parameters of theleading ground engaging segment 622 l and the trailing ground engagingsegment 622 t is below the predetermined threshold.

In other embodiments, the sensing devices 1122, 1152 of the monitoringsensors 1100 are arranged and configured as accelerometers. The sensingdevices 1122, 1152 are configured to send signals to the track systemcontroller 1000, the master control unit 1010 and/or the remote mastercontrol unit 1050 indicative of a vibration parameter undergone by theendless track 600. The vibration parameter may be representative of aninstantaneous frequency and amplitude of vibration, an average frequencyand amplitude of vibration over a certain period of time, a peakacceleration undergone by the endless track 600, or any other suitablevibration-related data. The vibration parameter is indicative of a stateof the track system 40 and, under certain circumstances, indicative ofthe ground surface condition. For example, a vibration parameter outsideof a predetermined range could be indicative of a lack or excess oftension in some portions of the endless track 600. The track systemcontroller 1000, the master control unit 1010 and/or the remote mastercontrol unit 1050 could operate the tensioner 420 so as to maintain thevibration parameter within the predetermined range, which could reducepremature wear of the endless track 600 in certain circumstances.

In other embodiments, the sensing devices 1122, 1152 of the monitoringsensors 1100 are arranged and configured as inclinometers. The sensingdevices 1122, 1152 are configured to send signals to the track systemcontroller 1000, the master control unit 1010 and/or the remote mastercontrol unit 1050 indicative of the camber angle θ of the axleassemblies connecting the idler and support wheel assemblies 400 l, 400t, 410 a, 410 b, 410 c to the frame assembly 200 relative to the plane190 (FIGS. 5 and 6). The camber angle θ of the axle assemblies is alsoindicative of a state of the track system 40 and, under certaincircumstances, indicative of the ground surface condition. Similar towhat has been described above, the signals generated by theinclinometers are provided to the track system controller 1000 whichoperates the actuator assembly 140 to adjust the positioning of theframe assembly 200 and the idler and support wheel assemblies 400 l, 400t, 410 a, 410 b, 410 c relative to the chassis 62 and/or the groundsurface in accordance with a predetermined objective. In someembodiments, the signals provided by the inclinometers could be used bythe track system controller 1000 to assess and calibrate the operationof the actuator assembly 140 and/or to assess the wear of the tread 606of the endless track 600.

In other embodiments, the sensing devices 1122, 1152 of the monitoringsensors 1100 are arranged and configured as temperature sensors. In someembodiments, the sensing devices 1122, 1152 are arranged asthermocouples or thermistors. The sensing devices 1122, 1152 areconfigured to send signals to the track system controller 1000, themaster control unit 1010 and/or the remote master control unit 1050indicative of a temperature parameter prevailing in the correspondingregions of the endless track 600. The temperature parameter may berepresentative of an instantaneous temperature, an average temperatureover a certain period of time, a peak temperature or any other suitabletemperature-related data. The temperature parameter is also indicativeof a state of the track system 40.

In response to the signals indicative of the temperature parameter ofeach of the sensing devices 1122, 1152, the track system controller1000, the master control unit 1010 and/or the remote master control unit1050 operates each one of the actuator assemblies 140, 150 l, 150 t, 310l, 310 t, 420, alone or in combination, so as to adjust the positioningof the frame assembly 200 and the idler and support wheel assemblies 400l, 400 t, 410 a, 410 b, 410 c relative to the chassis 62 and/or theground surface in accordance with a predetermined objective, which canbe in certain conditions to more evenly distribute the load across theground engaging segment 622 of the endless track 600.

For example, in an illustrative scenario, the track system controller1000, the master control unit 1010 and/or the remote master control unit1050 receives and processes signals from the sensing devices 1122, 1152indicative that the temperature parameter of the inward portion 616 ofthe endless track 600 is greater than the temperature parameter of theoutward portion 618 of the endless track 600 and that the differencebetween the temperature parameters is above a predetermined threshold.The track system controller 1000, the master control unit 1010 and/orthe remote master control unit 1050 operates the actuator assembly 140so as to change the camber angle θ in accordance with the predeterminedobjective of, for example, more evenly distributing the load across theground engaging segment 622 of the endless track 600. The track systemcontroller 1000 continues receiving and processing the signals from thetemperature sensors 1120 indicative of the temperature parameter of theendless track 600 until the difference between the temperatureparameters of the inward and outward portions 616, 618 of the endlesstrack 600 is below the predetermined threshold.

In other embodiments, any one of the sensing devices 1122, 1152 of themonitoring sensors 1100 mentioned above may be used in conjunction withany one of the other sensing devices to obtain additional data. Undercertain conditions, this will be useful, for example, to identify faultysensors.

Modifications and improvements to the above-described embodiments of thepresent technology may become apparent to those skilled in the art. Theforegoing description is intended to be exemplary rather than limiting.The scope of the present technology is therefore intended to be limitedsolely by the scope of the appended claims.

1. A track system for use with a vehicle having a chassis, the tracksystem comprising: an attachment assembly connectable to the chassis ofthe vehicle; a frame assembly disposed laterally outwardly from theattachment assembly and connected to the attachment assembly, the frameassembly including at least one wheel-bearing frame member; a leadingidler wheel assembly at least indirectly connected to the at least onewheel-bearing frame member; a trailing idler wheel assembly at leastindirectly connected to the at least one wheel-bearing frame member; atleast one support wheel assembly at least indirectly connected to the atleast one wheel-bearing frame member and disposed between the leadingidler wheel assembly and the trailing idler wheel assembly; an endlesstrack extending around the leading idler wheel assembly, the trailingidler wheel assembly, and the at least one support wheel assembly; atleast one monitoring sensor connected to the endless track, the at leastone monitoring sensor including an array of sensing devices and beingconfigured to generate at least one signal, the at least one monitoringsensor determining, at least indirectly, at least one of a state of thetrack system and a ground surface condition; and a track systemcontroller communicating with the at least one monitoring sensor forreceiving the at least one signal indicative of the at least one of thestate of the track system and the ground surface condition.
 2. The tracksystem of claim 1, wherein the at least one monitoring sensor isconfigured to generate a first signal indicative of a load parametersupported by the endless track.
 3. The track system of claim 2, whereinthe at least one monitoring sensor includes at least one of straingauges and load cells.
 4. The track system of claim 1, wherein the atleast one monitoring sensor is configured to generate a second signalindicative of a vibration parameter undergone by the endless track. 5.The track system of claim 4, wherein the at least one monitoring sensorincludes at least one of an accelerometer and an inclinometer.
 6. Thetrack system of claim 1, wherein the at least one monitoring sensor isconfigured to generate a third signal indicative of a temperatureparameter of the endless track.
 7. The track system of claim 6, whereinthe at least one monitoring sensor includes at least one of athermocouple and a thermistor.
 8. The track system of claim 1, whereinthe at least one monitoring sensor is embedded in the endless track. 9.The track system of claim 8, wherein the at least one monitoring sensoris a flexible mat structured and dimensioned to extend over a majorityof a width of the endless track.
 10. The track system of claim 8,wherein the at least one monitoring sensor is structured and dimensionedto extend along a majority of a length of the endless track.
 11. Thetrack system of claim 1, wherein the at least one monitoring sensorincludes a flexible foil connected to an inner surface of the endlesstrack.
 12. The track system of claim 11, wherein the foil is structuredand dimensioned to extend over a minority of a width of the endlesstrack.
 13. The track system of claim 11, wherein the foil is structuredand dimensioned to extend along a majority of a length of the endlesstrack.
 14. The track system of claim 11, wherein the at least onemonitoring sensor includes first and second flexible foils, the firstfoil is connected to an inward portion of the inner surface of theendless track, and the second foil is connected to an outward portion ofthe inner surface of the endless track.
 15. The track system of claim11, wherein the at least one monitoring sensor is connected to theendless track after a manufacturing of the endless track.
 16. The tracksystem of claim 1, wherein: the attachment assembly includes amulti-pivot assembly having a first pivot extending longitudinally anddefining a roll pivot axis of the track system, the frame assembly beingpivotable about the roll pivot axis, and a second pivot extendingvertically and defining a yaw pivot axis of the track system, the frameassembly being pivotable about the yaw pivot axis; the track systemfurther includes at least one actuator connected between the attachmentassembly and the frame assembly for pivoting the frame assembly about atleast one of the roll pivot axis and the yaw pivot axis; and the tracksystem controller is configured to connect to and to control theoperation of the at least one actuator based on the at least one of thestate of the track system and the ground surface condition.
 17. Avehicle comprising first and second track systems as claimed in claim 1,wherein the track system controller of the first track system is atleast indirectly connected to the track system controller of the secondtrack system for receiving the at least one signal indicative of the atleast one of the state of the track system and the ground surfacecondition determined by the at least one monitoring sensor of the secondtrack system.
 18. An endless track for a track system, comprising atleast one monitoring sensor including an array of sensing devices fordetermining, at least indirectly, at least one of a state of the tracksystem and a ground surface condition, the at least one monitoringsensor being structured and dimensioned to extend along a majority of alength of the endless track.
 19. The endless track of claim 18, whereinthe at least one monitoring sensor is structured and dimensioned toextend over a minority of a width of the endless track.
 20. The tracksystem of claim 18, wherein the at least one monitoring sensor isstructured and dimensioned to extend along a majority of a width of theendless track.